JPH0262080B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a line concentration distribution system that handles data by time division. [Technical background of the invention and its problems] When forming a network using a private branch exchange (hereinafter abbreviated as PBX), it is necessary to connect a mobile terminal or all buildings or floors directly to the PBX. Wiring is a very difficult task and is not convenient for use. Therefore, as shown in FIG. 1, a line concentration distribution device 11 is installed on each building and each floor, and the voice data from a plurality of terminals 13 such as telephones are transmitted to the line concentration distribution device 11 in a time-divided manner. multiplexed,
Data is transmitted to the central device 19 through one concentrator transmission line 17 and one distribution transmission line 15. When such a system is formed, it is easy to install a system consisting of the central device 19 and the line concentration/distribution device 11, which serve as the backbone. Furthermore, the terminal 13 is incorporated into a system centered on the PBX by simply connecting it to the line concentrator/distributor 11 installed at the nearest location, making the switching network extremely flexible. However, such a system has an unavoidable drawback because one transmission line 15, 17 is used in a time-division manner. That is, the signal transmission time differs depending on the position on the transmission lines 15, 17 to which the terminal is connected, and the line concentrator/distributor 11 is connected to every point on the transmission lines 15, 17. , 17, resulting in signal collisions or surplus blanks. This will be explained in detail. The signal from the central device 19 to the concentrator/distributor 11, that is, the signal on the distribution transmission line 11, is as shown in FIG. 2a.
The synchronization signal part SOa, consisting of a synchronization signal part SOa and a data signal part DOa, is sent from the central unit 19 to A
This indicates that the signal is directed to the line concentrator/distributor 11. Such signals are time-division multiplexed and transmitted on the distribution transmission line 17. It is assumed that each concentrator/distributor 11 sends it to the signal concentrator transmission line 15 immediately after detecting the synchronous signal portion SOa for itself. The signal on the concentrator transmission line 15 consists of a synchronization signal portion SIa and a data signal portion DIa, as shown in FIG. 2b. The synchronizing signal portion SIa represents a signal directed from the line concentrator/distributor 11 called A to the central unit 19. Now, the line concentrator/distributor 11 called A is connected to the transmission line 1
A concentrator/distributor 11 called B is connected to the farthest point from the central device 19 on the transmission lines 15 and 17 (referred to as the far end point). (referred to as the end point). However, the signal transmission delay time between the near end point and the central device 19 is set to zero, and the signal transmission delay time between the far end point and the central device 19 is assumed to be tl. At this time, as shown in FIG. 2a, it is assumed that the central device 19 sends out signals directed to the A and B concentrators and distributors 11 onto the distribution transmission line 17 at an interval τ. It is also assumed that the line concentrator/distributor transmits a signal to the central unit after a certain period of time after receiving the signal addressed to it from the central unit (in FIG. 2, immediately after detecting the synchronization signal). Then, as shown in FIG. Signal Fig. 2b assuming that
It is delayed by 2tl compared to . Furthermore, when the signals sent from the line concentrators 11 and 13 at the near end points are input to the central unit 19, they become as shown in FIG. 2d, and there is no time delay. Therefore, the signal interval τ on the distribution transmission line 17
is smaller than 2tl, the signal on the concentrator transmission line 17 is
If there is overlap (collision) and τ is larger than 2tl, a blank space will occur between the signals on the concentrator transmission line 15. Naturally, signal collision is unfavorable for signal transmission. When a blank space occurs between signals, the rate at which signals can actually be sent decreases, resulting in poor efficiency. Furthermore, the number of line concentrators 11 connected to the pair of transmission lines 15 and 17 must be reduced. As a means to solve this problem, the transmission delay time between the two points connecting the adjacent concentrators and distributors 11 to the transmission lines 15 and 17 is measured, and the signals on the distribution transmission line 17 are It is also effective to set a blank time (space). For example, 2
If the transmission delay time between points is tab, then the central device 1
Distribution transmission line 17 from 9 to line concentrator 11
The space between the signals above can be set to an appropriate value of 2 tabs or more. However, such means do not allow flexible configuration of the system. For example, when adding the line concentrator/distributor 11, it becomes necessary to make major changes to the system, such as measuring the delay time and changing the signal generation time. [Object of the Invention] It is an object of the present invention to eliminate the above-mentioned drawbacks and provide a new and flexible line concentration and distribution system. [Summary of the Invention] The present invention provides a system that connects a plurality of concentration distribution terminals to a pair of transmission paths from a central device. The first transmission line carries signals from each concentration distribution terminal in a time-division manner and transmits them to the central equipment, and the second transmission line carries signals from each concentration distribution terminal 21 from the central equipment to each concentration distribution terminal 21.
The signals going to the station are transmitted in a time-division manner. In such a system, the central device detects a collision of signals on the first transmission path, and in order to control this collision, the transmission time of the signal from the concentration distribution terminal to the central device is corrected. be. To achieve this, the central device includes a collision detection circuit and a control signal generation circuit, and the line concentration and distribution terminal includes a control signal detection circuit and a signal transmission time control circuit. That is, the collision detection circuit detects whether or not there is a collision between the signals on the first transmission path when the signals are input to the first receiving means in the central device. In order to notify the line concentration and distribution terminal of this detection result, a control signal carrying the detection result is generated by a control signal generation circuit and sent to the line concentration and distribution terminal. At the line concentration distribution terminal, the control signal detection circuit detects this control signal and sends it to the signal transmission time control circuit. The signal sending time control circuit corrects the timing of the signal sent from the line concentration distribution terminal according to this control signal. The signal whose transmission timing has been corrected goes to the central device again, and when it is input to the first receiving means,
If a collision occurs, control is reapplied. [Effects of the Invention] According to the present invention, since signal collisions are detected and the timing of transmitting signals from the line concentration distribution terminal to the central device is corrected according to the detection result, signal collisions can be controlled. Moreover, it does not depend on where on the first and second transmission paths the line concentration distribution terminal is connected. Therefore, even if a new line concentration/distribution terminal is connected to a pair of transmission lines, signal collisions can be quickly controlled. [Embodiment of the Invention] Next, an embodiment of the invention will be described. This embodiment relates to a system using a private branch exchange as the central unit. As shown in FIG. 3, this system consists of a central device 32, a line concentrator and distributor 33, and a terminal 35. Terminal 35 is, for example, a telephone. A line concentration/distribution terminal in the scope of the claims is a means consisting of one line concentration/distribution device 33 and at least one terminal connected thereto. The central device 31 has exchange capability. A plurality of line concentrators and distributors 33 are connected to the distribution transmission line 37 and line concentrator transmission line 39 from the central device 31 via introduction lines 41a and 41b. The concentrator/distributor 33 has the ability to time-division multiplex information from a plurality of terminals 35 and send it onto the concentrator transmission line 39, and the ability to distribute the signal from the distribution transmission line 37 to each terminal 35. Note that the concentrating transmission line and the distribution transmission line do not need to be separate cables, and a single cable may be used by dividing the bands. As described above, in the present invention, collisions of signals on the transmission lines 37 and 39 are detected in the central device 31. This detection result is sent to the line concentration distribution device 33. The line concentrator/distributor 33 controls the timing of the signal word to be transmitted according to this detection result. That is, if a signal on the transmission line 39 is detected, the transmission timing from the integrated distribution device 33 can be changed to eliminate signal collision on the transmission line 39. Next, the central device 31 will be explained. A preferred embodiment of this central unit 31 is shown in FIG. The concentrator transmission line 39 is connected to the receiver 41 . This receiver 41 converts the signal on the concentrator transmission line 39 into a logic level. The output of the receiver 41 is input to a synchronization signal detection circuit 43. The synchronization signal detection circuit 43 detects which concentrator/distributor 33 the signal input from the concentrator transmission line 39 to the central device 31 comes from. The signal on the concentrator transmission line 39 is sent to the collision detection circuit 4
5. Also input to the space over detection circuit 47. The collision detection circuit 45 detects a collision of signals on the concentrator transmission line 39. A space over detection circuit 47 detects a blank space between signals on the concentrator transmission line 39. The outputs from the collision detection circuit 45 and the space over detection circuit 47 are input to the control signal generation circuit 49 together with the output from the synchronization signal detection circuit 43. The control signal generation circuit 49 generates a signal depending on the collision between signals and the presence or absence of a blank space. On the other hand, the output of the receiver 41 is input to the distribution circuit 75. The distribution circuit 75 separates the time-division multiplexed signals into individual signals and sends and outputs them to each wire drawing distribution device 33 to be transmitted. The output of this distribution circuit 75 is input to an exchange 77. This exchange 77 divides the signal into signals up to the individual telephones 35, performs exchange processing, and outputs the signal again as a signal for each line concentrator/distributor 33. The output of this exchange 77 is input to the multiplexing circuit 53. In this multiplexing circuit 53, the output from the exchange 77 is used as a data signal portion, and a synchronization signal and a control signal from the control signal generation circuit 49 described above are added thereto. Further, a signal sent to each line concentrator/distributor 33 is made into one word, and a plurality of words are time-division multiplexed. This will be discussed later. The output of this multiplexing circuit 53 is input to a transmitter 55. This transmitter 55 outputs the signal multiplexed by the multiplexing circuit 53 onto the distribution transmission line 37. It is important that the signal on the distribution transmission path 37, that is, the signal sent to each concentrator/distributor 33, includes the aforementioned control signal. A feature of this embodiment is that this control signal is generated not only from the collision of signals on the concentrator transmission line 39 but also from the space between the signals (space over). However, the form of this control signal does not have to be the collision detection signal or space over signal itself. Each part of the central device 31 will be explained below. First, the signal on the wireless transmission path 39 is a signal transmitted from each line concentrator/distributor 33 and directed to the central device 31, and is configured in units of words. The word structure of this signal consists of a synchronization signal portion SIi and a data signal portion DIi, as shown in FIG. The synchronization signal portion SIi represents the signal coming from the i-th line concentrator/distributor 33. i is a subscript representing the number of the line concentrator/distributor 33. These words are collected in a number equal to the number of line concentrators and distributors 33, and constitute an I frame. At this time, these words are time-division multiplexed. Various encoding methods and modulation methods can be considered for such signals (on the distribution transmission line 37 and the concentrating transmission line 39). Accordingly, methods for detecting collisions will become clearer. In this embodiment, the signals on the transmission lines 37 and 39 are subjected to die phase encoding. A die phase code is represented by changing from a 0 level to a 1 level, or from a 1 level to a 0 level, at the center of a time slot, corresponding to a binary "0". Corresponding to a binary "1", there is no level change over the entire time slot, for example, it is represented by a signal that remains at 0 level and 1 level. Also, on the expiration date of the time slot,
There are always changes in level. Furthermore, it is assumed that the signal is held at 0 level in areas where there is no signal. Now, send the signal string "0101110010" to line transmission line 3.
Suppose that it is transmitted at 9. Assuming that these signals are generated from time _t1 to tn, when the die-phase code described above is applied, the signals will become as shown in FIG. 7b. This signal is the signal on the actual concentrator transmission line 39. As mentioned above, the signals on the concentrator transmission line 39 may collide, and the spacing between signals may be greater than necessary. In this embodiment, collisions and spaces between signals on the concentrator transmission line 39 are detected by a collision detection circuit 45 and a space over detection circuit 47 as described below. The collision detection circuit 45 includes a low pass filter (hereinafter abbreviated as LPF) 57 as shown in FIG.
, a first comparator 59, and a first mono multivibrator 61. In die-phase encoding as shown in FIG. 6b, if no signal is transmitted, the signal on the transmission path is at 0 level. However, when a signal is transmitted, at least a DC component is generated. Therefore,
When the signal shown in FIG. 6b is input to the LPF 57, the signal shown in FIG. 6c is obtained as an output. Assume that two signals as shown in FIG. 6d and e are generated on the concentrator transmission line 39. Concentrated transmission line 39
Then, the two signals are superimposed and transmitted as the signal shown in FIG. 6f, which is input to the LPF 57. Then, the output of the LPF 57 becomes a signal as shown in FIG. 6g. Since the signals shown in FIGS. 6d and 6 each have a DC component, the output of the LPF 57 is approximately doubled due to the collision. Low frequencies pass through the transmission path more easily. Therefore, even if the transmission path 39 is long, a signal as shown in FIG. 6g can be detected correctly. Therefore, in the first comparator 59, a first threshold value SH1 is set. This threshold value SH1 is set to 1.5D with respect to the amplitude D of the DC component of one signal. The output of the LPF 57 is input to the first comparator 59, and the first threshold SH1 is used as a reference signal. Therefore, when the two signals overlap on the concentrator transmission line 39, that is, when the two signals collide, the output of the first comparator 59 becomes "1". The output "1" of the first comparator 59 sets the first mono multivibrator 61. The first mono-multivibrator 61 generates a collision detection signal that is a pulse signal with a predetermined time width. On the other hand, the space over detection circuit 47 includes an LPF 57 shared with the collision detection circuit 45, second and third comparators 65 and 67, a timer 69, and a second
It consists of a mono multivibrator 71. In the second comparator 65, a first threshold SH2 is set. This second threshold value SH2 is assumed to be 0.5D. With this threshold value SH2 as a reference, the output of the LPF 57 is used as the input signal of the second comparator 65. However, in the second comparator 65, the output signal becomes "1" only when the output signal of the LPF 57 is smaller than the second threshold value SH2. The output of the second comparator 65 is input to a timer 69. This timer 69 starts operating when the signal "1" is input. Further, when a signal "0" is input to the timer 69, it is reset. Therefore, this timer 69 measures the blank time between two signals. The contents of this timer 69 are compared in a third comparator 67 with the maximum allowable blank time Sm. This allowable time Sm is a time interval allowed as a space between signals. It is undesirable in terms of transmission efficiency for the space to continue for longer than this allowable time Sm, and is controlled in this embodiment. In this example, Sm=1.2△ (△ is
This is one clock time and will be explained in detail later. ). That is, in the third comparator 67, the timer 69
If the content of is greater than the allowable time Sm, a signal "1" is output. This signal "1" sets the second mono multivibrator 71. The second mono-multivibrator 71 outputs a space over signal 73 which is a pulse time of a predetermined width. In this way, the collision detection circuit 45 outputs the collision detection signal 63, and the space over detection circuit 47 outputs the space over signal. On the other hand, the signal on the concentrator transmission line 39 is input to the synchronization signal detection circuit 43 via the receiver 41. The signal converted to a logic level by the receiver 41 is
This synchronizing signal detection circuit 43 detects the synchronizing signal portion SIi. That is, SIi detects which line concentrator 33 each word comes from. A signal carrying this information, a control signal generation circuit 4
9 and distribution circuit 75. The control signal generation circuit 49 generates control signals as described later from the collision detection signal, space over signal, and synchronization detection signal, and generates control signals corresponding to each word when the multiplexing circuit 53 multiplexes the signals. Add. Further, the output of the receiver 41 is supplied to a distribution circuit 75. The signal from the exchange 77 is sent to each concentrator/distributor 33.
It is sent to the multiplexing circuit 53 as the data signal portion DOi destined for . As shown in FIG. 9, the multiplexing circuit 53 adds the synchronizing signal portion SOi and the control signal portion CTi from the control signal generating circuit 49 to the data signal portion DOi to form one word. Furthermore, by time-division multiplexing using multiple such words,
It is sent to the transmitter 55. That is, the words shown in FIG. 8 are collected by the line concentrator/distributor 33 to form one frame. However, considering the time relationship within the frame, that is, the order of each word is not changed, as shown in FIG.
DOi may be multiplexed and a frame synchronization signal FSY may be provided. At this time, the synchronization signal portion may be omitted. The line concentrator/distributor detects the FSY and knows at which word the word addressed to it is located, so it can extract the word addressed to itself. Furthermore, in the above figure, for the sake of simplicity,
All data signals are assumed to have the same length. However, as described later, each line concentrator/distributor 33
Since the transmission timing is controlled using a synchronization signal set for each time as a reference time, it can be applied even if all the signals have different data lengths. Next, the line concentrator/distributor 33 that receives such a signal from the central device 31 will be explained based on FIG. 10. The line concentrator and distributor 33 receives a signal from the central device 31 and sends a signal from the terminal 35 to the central device 31. And central device 3
The timing of sending the signal to 1 is controlled based on the above-mentioned control signal. This integrated distribution device 33 uses a receiver 79 to convert the signal from the distribution transmission line 37, that is, the signal directed from the central device 31 to the line concentration distribution device 33 as shown in FIG. 8 as described above, into a logic level. The converted signal is supplied to a synchronization signal detection circuit 81. This synchronization signal detection circuit 81 detects the synchronization signal portion SOi. This synchronization signal part SOi
When this is detected, it is known to which concentrator/distributor 33 the word with this is directed from the central device 32 . Therefore, the synchronization signal detection circuit 81 of the i-th line concentrator and distribution device 33 detects the synchronization signal portion SOi
If this is detected, it is known that the word to which this signal is attached is a signal that is accepted by the line concentrator/distributor 33. The synchronization signal detection circuit 81 outputs a synchronization detection signal 82 in response to the detection of the synchronization signal portion.
This detection signal 82 is supplied to a control signal detection circuit 83 and a distribution circuit 85. Then, the control signal detection circuit 83 detects the detection signal 8
The control signal portion CTi is detected from the 1-word signal at the timing of 2. This control signal portion CTi includes information of a collision detection signal 63 and a space detection signal 65.The control signal detection circuit 83 detects the control signal
CTi as collision detection signal 63, space detection signal 65
Convert and output. At the same time, the distribution circuit 85 similarly distributes the data signal to the concentrator distribution device 33.
Import only DOi. The distribution circuit 85 has the function of a kind of gate circuit controlled by the synchronization detection signal. The distribution circuit 85 separates the captured data signal portion DOi for each terminal 35. The separated signals are provided to terminal interface 87.
Terminal interface 87 supplied with signals
sends a signal to each terminal 35. Further, the signal from the terminal 35 is sent to the multi-shielding circuit 91. When the terminal 35 is a telephone, the frosty interface 87 includes a DA converter that converts the digital signal from the distribution circuit 85 into an analog signal;
It consists of an AD converter, a hybrid transformer, etc. that converts analog signals from telephones into digital signals. Signals from a plurality of terminal interfaces 87 are time-division multiplexed in a multiplexing circuit 91 at a timing determined by a synchronization detection signal 82 obtained by a synchronization signal detection circuit 81. At this time, the synchronization signal part is added to the data signal part DIi obtained by time division multiplexing.
Add SIi to make it a 1-word signal. The output of the multiplexing circuit 91 is supplied to a signal transmission time control circuit 89. This signal sending time control circuit 89 is also supplied with the collision detection signal 62 and space detection signal 72 from the control signal detection circuit 83, and based on these signals 63 and 73, the output of the multiplexing circuit 91 is sent via the transmitter 93. The timing of sending to the concentrator transmission line 39 is controlled based on the detection timing of the periodic signal 82. This control will be described later. Further, the collision detection signal 62 here is a signal indicating that a collision has occurred, and is not necessarily the same as the collision detection signal 63 in the central device 32 described above. The same applies to the space detection signal 72. The transmitter 93 encodes this one-word signal (modulates it if necessary) and sends it to the concentrator transmission line 93. This sending timing is controlled by a signal sending time control circuit 89. This signal is
It goes to the central device 31 via the wireless transmission path 39.
1 from each concentration distribution device 33 to this concentration transmission line 39
When the word signals are transmitted, the transmission timing is controlled so that collisions between words and surplus blanks do not occur. The control will be explained below. For convenience of explanation, in this embodiment, each line concentrator/distributor 33 has transmission lines 37, 3 as shown in FIG.
It is assumed that the wireless distribution devices A, B, C, and D are connected in sequence from the far end point to the near end point. Here, the far end point is the receiver 4 of the central device 31.
1. On the transmission lines 37 and 39 for the transmitter 55,
This is the farthest point to which the wireless distribution device 33 is connected. Conversely, the near end point is the receiver 4 of the central unit 31.
1. This is the closest point to the transmitter 55 on the transmission lines 37 and 39 to which the line concentrator and distributor 33 is connected. From the central device 32 to the line concentration distribution devices A, B, C, D
One-way signal transmission time up to 6△, 3.5△, 3△,
1△1△ is a unit time determined by the required control time accuracy. ). Now, from the central device 32,
As shown in FIG. 11a, the signal frame to be sent to the line concentrator/distributor 33 via the distribution transmission line 37 is constructed in succession as WOa, WOb, WOc, and WOd. Between each frame, as described below,
Leave some space SO. Here, subscript a,
b, c, and d correspond to the line concentration distribution devices A, B, C, and D. WOa is a word directed to line concentrator/distributor A, and so on. Each word consists of a synchronization signal portion SOi, a control signal portion CTi, and a data signal portion DOi, as shown in FIG. Normally, the data signal portion DOi is time-division multiplexed with signals destined for a plurality of terminals 35 connected to the line concentrator 33. In this embodiment, the time control is performed by detecting a synchronization signal of the wire heading toward the concentrator/distributor 32 in each concentrator/distributor 33.
The time when SOi is detected is set as the reference time. In each line concentrator/distributor 33, the time from the input of the word addressed to itself until the detection of the synchronization signal portion SOi is all equal to Ts. Also, from the reference time Ti(i
= a, b, c, d) After the line concentrator distribution device A, B,
It is assumed that signals are sent from C and D on the concentrator transmission line 39. This Ti is a control signal and is controlled by the signal sending time control circuit 89. There are several time control algorithms for the signal transmission time control circuit 89. However, since the control in the signal transmission time control circuit 89 is based on the control signal from the control signal generation circuit 32 of the central device 32, it can be said that there are many algorithms for generating this control signal. ◎About the first algorithm (1) The generation time of the first word of the frame is not controlled. (2) Of the two words that caused the collision, the transmission timing of the word from the concentrator/distributor 33 that generated the latter signal to the central device 32 is set △
only delay. That is, the delay time is increased. (3) Space over occurred between words 2
Of the two words, the transmission timing of the word destined for the integrated distribution device 33 or the central device 32 that generated the latter signal is advanced by Δ. That is, the delay time is reduced. That is what it is. That is, if a collision or space over is detected between two signals, the control time Ti is adjusted in the concentrator/distributor 33 corresponding to the later word in the frame structure. Here, as the initial value of Ti, Ta=Tb=Tc=Td
=5△. Each word is sent from the central unit 32 to the line concentrators B, D,
When sent to A, C, each concentrator/distributor B, at the timing shown in FIGS.
Words are sent from D, A, and C onto the concentrator transmission line 39. This timing is the time required to transmit on the transmission line 37 to the line concentrators B, D, A, and C (3.5△, △, 6△, 3△), and the time required to detect the synchronization signal part. It is determined by Ts and the control time (initial value 5Δ, which corresponds to the delay time). In addition, WIi is connected from the line concentrator I to the central unit 3.
This is the word sent to 2. Furthermore, it takes a finite time for transmission from each concentrator/distributor B, D, A, C to the central device 32, and as mentioned above, the time is 3.5△, △, 6△, 3△. Therefore, when inputting from the concentrator transmission line 39 to the central device 32 (more precisely, the receiver 41), it becomes as shown in FIG. 11f. In this figure, collisions Q1 and Q2 are shown in the shaded areas.
is generated, and spaces S1 and S2 are generated. This situation is shown numerically in Table 1, where the number of controls n _c =
This is a 0 line.

[Table] The number of controls n _c is the number of significant controls performed by the signal sending time control circuit 89 for the control time Ti. The interword time Si,i+1 indicates the relationship between the two inherited words WIi and WIi ₊₁ . Collisions Q1, Q2, spaces S1, S2 in Figure 12 f
A negative number indicates a collision, and a positive number indicates a space. For example, Sbd indicates the relationship between the words WIb and WId, and in this example, since it is a collision and a 5Δ collision, it is −5Δ. below,
The same is true. The method for calculating the time when a collision occurs and the time when a space occurs will be explained later, just in case. Now, when the signal shown in FIG.
At , space overs S1 and S2 are detected. In this algorithm, even when the spacing between words is zero, it is considered a collision.
For this purpose, a collision detection circuit 4 shown in FIG.
5 needs to be slightly modified. That is,
When the output of the LPF 57 has an amplitude greater than a certain value and is longer than a predetermined word length, it is necessary to modify the collision detection signal 63 to be "1". On the other hand, in the synchronization signal detection circuit 43, the synchronization signal section
SIb and Sia can be detected, but collision Q
1, the synchronization signal portion Sid cannot be detected.
The control signal generation circuit 49 determines that a collision has occurred in words WIb and WId based on SIb, and generates a control signal.
Generates CTd. CTd becomes "+". Here, the control signal generation circuit 49 needs to know the structure of words within the frame. The frame configuration is information that is naturally established during multiplexing in the multiplexing circuit 53, regardless of the connection position of the line concentrator/distributor 33, and can also be referenced in the control signal generating circuit 49. The same is true for collision Q2, where it is detected that it has occurred in words WIa and Wic, and CTc becomes "+". Similar processing is performed for space overs S1 and S2. That is, the detected synchronization signal portions are SIb and SIa, and space over S1 is detected between them. Space over S
Since word 1 is located immediately before SIa, it can be determined that word 1 is between WId and WIa, and the control signal CTa is set to "-" corresponding to word WIa. Similarly, since space over S2 is detected immediately before SIb belonging to the first word of the next frame, the control signal should be set corresponding to WIb, but as shown in (1) above, This algorithm does not control the first word of the frame, so it is left as is. Note that SId was not detected due to collision Q1, but since collision Q1 occurred after SIb was detected, the next word, i.e.
It can also be determined that it has moved to WId. This determination makes it even more likely that S1 is between WId and WIa. In this way, the control signal CTi is set and
The multiplexing circuit 5 has a word configuration as shown in FIG.
3, a frame is defined and the transmitter 55
It is sent out from. Here, since the control signal CTi only needs to represent the three states of + and zero-, 2 bits is sufficient. In the circuit shown in FIG. 8, CTi being "+" is represented by the collision detection signal 63 being "1" and the space over detection signal 73 being "0". The fact that CTi is "0" is indicated by the fact that both the collision detection signal 63 and the space over detection signal 73 are "0". CTi is "-" means that the collision detection signal 63 is "0" and the space over detection signal 7 is "0".
It is represented by 3 being ``1''. A word containing such a control signal CTi is supplied to the line concentrator/distributor 33. This control signal CTi
are separated and detected in the control signal detection circuit 83 using the synchronization detection signal 83. Then, the collision detection signal 63 and the space over detection signal 73 are sent to the signal sending time control circuit 89. The signal sending time control circuit 89 receives the collision detection signal 6
When 3 is "1" (corresponding to the case where CTi described above is "+"), the control time Ti is increased by Δ. When the space over detection signal 73 is "1" (as described above)
(corresponding to when CTi is "-") Decrease control time Ti by △. If both signals 63 and 73 are "0" (corresponding to the case where the above-mentioned CTi is "0"), the control time is not changed. Therefore, the control times Tb, Td, Ta, and Tc of the first significant control of the concentrators and distributors B, D, A, and C using the control signal CTi at the time of n _c =0 are as follows.
They change by 0, +△, -△, and +△, respectively. Therefore, the control time (delay time) Tb when n _c =1,
Td, Ta, and Tc are 5△, 6△, -4△, and 6△. As a result, the received signal at the central device 32 is
As shown in Figure 12g, collisions Q1, Q2,
Both spaces S1 and S2 are decreasing. Similar processing will be performed thereafter. Then, when n _c =8,
Inter-word spacing Sbd, Sda, Sac, Scb are △, △,
△, 2△, and the control ends. As mentioned above, the time of occurrence of the word WIb at the beginning of the frame was fixed. However, if this is not fixed,
Since the space of Scb is larger than 1.2△, control continues further. Also, in this example, since some space has to exceed 1.2△, control continues,
Operation becomes unstable. Space margin SO on the distribution transmission line 37 (12th
Figure a is an example and should be interpreted as a margin of space within one frame. ) is determined by the minimum value depending on how much space is allowed between words on the concentrator transmission line 39. In this example, the maximum space between words Sm is 1.2△
Therefore, if WIi and WOi have the same length, SO needs to be 1.2Δ×4=4.8Δ or more. The length of one frame is the transmission line 37, 39
It can be understood by noting that the margin of space on the distribution transmission line 37 is allocated to the word spacing on the concentrator transmission line 39, since it is the same regardless of the transmission line. Next, a specific configuration of the control signal generation circuit 49 will be explained. This will be explained based on FIG. 13. The word number detected by the synchronization signal detection circuit 43 is supplied to the storage device 130 as information. The contents of storage device 130 are provided to decoding circuitry 132 . The decoding circuit 132 outputs a signal corresponding to the next word of the supplied word number. That is, the order of words in one frame is WOb, WOd, WOa, and WOc. At this time,
Once the synchronization signal component SIb is detected, this number b is temporarily stored in the storage device 130. Then, a signal corresponding to this b is supplied to the decoding circuit 132. The decoding circuit 132 supplies a signal "1" to the output terminal 134d corresponding to the word WOd following the word WOb. Here, normally, the exchange 77 includes the transmission line 37,
The connection status (position) of the line concentrator/distributor 33 connected to the line concentrator/distributor 39, the telephone 35, etc. The frame configuration is performed together with the conversion circuit 153. Therefore, even if the connection of the line concentrator 33, telephone 35, etc. changes, the exchange 77 naturally has information about the frame structure, and if this information is provided to the decoding circuit 132, the above problem can be solved. It's easy to do. Further, second to fourth output terminals 134a to 134d of the decoding circuit 132 are provided corresponding to first to fourth shift registers 136a to 134d. The first to fourth shift registers 136a to 136d are all two-stage shift registers. The output of the first output terminal 134a is supplied together with the collision detection signal 63 to the first AND circuit 138a, and together with the space over detection signal 73 to the second AND circuit 140a. The output of the first AND circuit 138a sets the previous stage bit of the first shift register 136a. The output of the second AND circuit 140a sets the subsequent bit of the first shift register 136a. The subsequent stage of the first shift register 136a is grounded. Further, the previous bit of the first shift register 136a becomes the control signal CTa. The same applies to the others, and the outputs of the previous stage bits of the second to fourth shift registers 136b to 136d become control signals CTb, CTc, and CTd, respectively. The function of the memory content rewriting circuit 142 will be explained. It is easy to understand if we consider a collision between two words, but when a collision occurs, the synchronization signal component located at the beginning of the next word overlaps with the data signal component of the previous word, and SIi overlaps with the data signal component of the previous word. Synchronization signal component SIi is not detected. Therefore, the storage content rewriting circuit 142 detects that the collision detection signal 87 changes from "1" to "0". Then, the contents of the storage device 130 are rewritten. Moreover, the word number stored in the storage device 130 is rewritten to the next word number. The order of the words is the order within the frame. In this way, the word up count is done. To explain with an example, first, the synchronization signal of WIb
“b” is stored in the storage circuit 130 by SIb,
By the post-sign circuit 132, the next word after word WIb is
Since it is WId, a signal "1" is output to the output 134d. The collision Q1 causes the collision signal to become "1", which causes the fourth shift register 136 to
The first stage of d is set to "1". Control signal
CTd becomes "10". This is equivalent to what is marked as "+" in Table 1. In other words, the line concentrator/distributor is ordered to delay the timing of signal generation. Next, when the collision signal ends, the memory circuit 130
The content changes from "b" to "d", and since the next word of WId is WIa, the output 134a becomes "1". Next, due to the space S1 in FIG. 11f, the inter-signal space over signal 73 becomes "1".
Therefore, the subsequent stage of shift register 136a is set to "1". Therefore, the control signal CTa becomes "01". This is equivalent to what is indicated by "-" in Table 1. In other words, the line concentrator/distributor 33 is ordered to advance the timing of signal generation. The multiplexing circuit 53 will be explained. The configuration shown in FIG. 14 is adopted. That is, exchange 7
The output signal from 7 is sent to the first to fourth memory circuits 14.
4a to 144d. 146a to 146d are synchronization signal generation circuits that generate synchronization signals SOa to SOd, respectively.
This can be done by using a parallel input serial output shift register to input a code corresponding to a synchronization signal to the parallel input. 148a to 148d are
These are control signal inputs and output signals of the first to fourth shift registers 136a to 136d shown in FIG. This signal is CTa, CTb, CTc,
CTd. The control clock generation circuit 148 is
A clock 150 synchronized with switch 77 is provided and generates a control gate clock 152. This clock corresponds to FIG. g, h, i, in FIG. 15 in order from the right side of the clock 152.
Corresponds to a, b, c, j, k, l, f. Control gate clock 152 is provided to AND-OR gate 154. On the other hand, the synchronizing signal generating circuits 146a to 146d serving as signal sources, the first
The fourth memory circuits 144a to 144d, the first
thru fourth shift registers 136a to 136d
A read clock is also supplied corresponding to this control gate clock 152. This is not shown. Next, a specific configuration of the signal sending time control circuit 89 will be explained. Signal sending time control circuit 89
is a reversible counter 9 as shown in FIG.
5 and the first to fourth shift registers 97, 9
Including 9,101,103. Further, this signal sending time control circuit 89 can control the control time (delay time) Ti with a time width of 15Δ. Collision detection signal 63 from control signal detection circuit 83
is input to the up count terminal of the reversible counter 95. When the signal 63 is "1", the content of the reversible counter 95 increases by "1". The space over detection signal 73 is input to the down count terminal of the reversible counter 95. When the signal 73 is "1", the content of the reversible counter 95 is decreased by "1". The output of this reversible counter 95 is 4 bits, starting from the highest: Q8 (N ³ ), Q4 (2 ² ), Q1 (2 ⁰ ).
shall be. On the other hand, the output of the multiplexing circuit 91 is the first
input into the shift register 97 of. At the same time, the signal is input to the first AND-OR circuit 107 together with Q8 via the inverter 105. This first AND-OR circuit 107 includes a first shift register 9
Along with the output of 7, Q8 is also input. The output of the first AND-OR circuit 107 is input to a second shift register 99 having four stages. The output of the second shift register 99 is input to the second AND-OR circuit 109 together with Q4. This second AND-OR circuit 109 includes an inverter 111 as well as an output of the first shift register 97.
Q4 inputs via. The output of the second AND-OR circuit 109 is input to the third shift register 101 having two stages. The output of the third shift register 101 is input to the third AND-OR circuit 113 together with Q2.
The third AND-OR circuit 113 includes an inverter 115 as well as an output of the second shift register 101.
Q2 via is input. The output of the third AND-OR circuit 113 is input to the fourth shift register 103, which is one stage. The output of the fourth shift register 103 is input to the fourth AND-OR circuit 117 together with Q1.
The fourth AND-OR circuit 117 includes an inverter 118 as well as the output of the third shift register 101.
Q1 inputs via. The output of the fourth AND-OR circuit 117 becomes the output of the signal transmission time control circuit 89. First to fourth AND-OR circuits 107, 10
The configurations of circuits 9, 113, and 117 are the same and consist of first and second AND circuits 119, 121 and an OR circuit 132. The first AND circuit 119 receives the outputs of the inverters 111, 115, and 118 as well as the outputs of the shift registers in the previous stage.
The output of the inverter 105 is input to the first AND circuit 119 together with the output of the multiplexing circuit 91 .
The second AND circuit 121 receives the bit outputs Q8, Q4, Q2, and Q1 of the reversible counter as well as the output of the shift register at the previous stage. 1st and 2nd
The outputs of the AND circuits 119 and 121 are input to the OR circuit 123. The output of the OR circuit 123 is the AND-OR circuit 107, 109, 113, 117
The output is With this configuration, the total number of stages of the shift register changes depending on the binary outputs Q8, Q4, Q2, and Q1 of the reversible counter 95, and the control time Ti, which is the delay time, changes. Regarding the second algorithm (1) The timing of sending any one word from the line concentrator/distributor 43 is fixed. (WIa in this example) (2) Of the two conflicting words, the control time Ti ((delay time) of the previous word is decreased by △. (3) Space over is detected. If the space over occurs, the control time Ti (delay time) of the previous word of the two words related to the space over is increased by △. (4) If the word time is zero, it is not treated as a collision. In this case, the control signal is given in the opposite way to the first algorithm.For example, if a collision occurs, one of the two words is
Since the previous word is controlled, the control signal generating circuit 49 needs to change the previous word control signal CTi. In the first algorithm, collisions are represented as "+", but in the second algorithm, collisions are represented as "-".
It is expressed as This is because eliminating collisions requires moving either word in opposite directions. The same applies to over space. child

In the second algorithm in [Table], the above-mentioned (2) and (3) are the key points, and the other limitations are not so essential. Table 2 shows the state of control according to this algorithm. As can be seen from this table, the interword times Sbd, Sda, Sac, and Scb are △, △, 2
△, △ indicates that the control operation has been completed. ◎About the third algorithm (1) All control times Ti are changed. That is,
Controls the timing of sending words from all line concentrators and distributors A, B, C, and D. (2) Determine the direction of change in control time Ti as shown in Table 3. (3) If the space between words is zero, it is not considered a collision.

【table】

[Table] In other words, this algorithm is based on moving the word to an empty space. Table 4 shows the control operation according to this algorithm.

[Table] The first to third algorithms explained above all operate on the concentrator transmission line 3 in the central device 32.
Collisions and space overs between words on 9 are detected, and based on the detection results, it is determined whether to simply increase, decrease, or maintain the control time Ti in the line concentration distribution device 33,
The direction of the control is notified to each line concentrator/separator 33. ◎Fourth Algorithm If the collision detection circuit 45 detects up to the length of the collision, and the space over detection circuit 47 detects up to the length of the space over between words, control becomes easier. In other words, if the control signal is a 2-bit or more signal that takes these time lengths into consideration and the control time is varied by an integer multiple of Δ instead of the unit time Δ, the control can be performed more quickly. For example, in the basic algorithm, similar to the first algorithm, control is applied to subsequent words, and the control time Ti is changed as follows. (1) If the collision length is 2△ or more, increase it by +2△. (2) If the collision length is less than 2△, increase it by △. (3) If the inter-word space is 3△ or more, decrease it by 2△. (4) If the interword space is less than 3△ and greater than 1.2△, it can be reduced by △. (5) If the inter-word space is 1.2△ or less, do not change it. (6) If the space between words is zero, it is not considered a collision. In this way, the control signal has 3 bits.

【table】

[Table] Figure 5 shows the control operation when this algorithm is followed. Compared to the control shown in FIG. 1, convergence is significantly faster. ◎Fifth Algorithm In the above, control was performed by changing the control time Ti each time, but if you have a means to measure the length of the collision and the length of the interword space, you can control it by one time. Interword space is greater than zero
It is also possible to do this so that it is 1.2△ or less.
Let the initial measured values of the word times Sbd, Sda, Sac, and Scb mentioned above be Sbd゜, Sda°, Sac°, and Scb゜, and the control time Tb at the line concentrator and distribution device B corresponding to the first word of the frame is fixed. . Then, the control time Td in each concentrator/distributor D, A, C,
Considering that the necessary changes Rd, Ra, and Rc of Ta and Tc represent collisions with negative numbers and space overs with positive numbers, the control time Td of the concentrator and distributor D is calculated from the concentrators and distributors B and D. Since the target is between words, the condition 0<Sbd゜+Rd1.2△ is applied. Similarly, the control time Ta,
Tc is subject to the following conditions: 0<Sda°-Rd+Ra1.2△ 0<Sac°-Ra+Rc1.2△. The key is to pay attention to the relationship between the two words. As mentioned above, since Sbd゜=-5△, Sda゜=10△, and Sac゜=-6△, 5△<Rd6.2△, and Rd=6△ is selected. Similarly, -4△<Ra-2.8△, and Ra=-3△. Also, 3△<Rc4.20, and Rc=4△. The reason why an integer multiple of Δ was selected as Ri was for practical reasons. From the above, by increasing the number of bits of the control signal,
For example, if the amount of change is used as the control signal,
CTb=0, CTd=6, CTa=-3, CTc=4
If you send , you can converge all at once. ◎Sixth Algorithm As is clear from the above explanation, it is collisions between words that cause signal errors. Focusing on this point, a sixth algorithm that performs control by detecting only collisions between words without detecting space overs between words will be described. (1) Change all control times. (2) Control time Ti in the concentrator/distributor 33 where a collision occurs between words or a later word is generated
increase. (3) If the space between words is zero, it is considered a collision. This is why Table 6 shows numerically the processing by this sixth algorithm.

[Table] This algorithm constantly increases the control time of later beliefs based on collisions, but
By switching between reducing the control time of the previous word and reducing the control signal of the subsequent signal depending on the time, the control capacity of the hardware can be suppressed. Similarly, it is also possible to detect and control only space overs between words, rather than collisions. At this time, the key is to select a threshold value for determining space over. For example, if there is a collision somewhere, it is necessary to choose a threshold so that overspace is detected elsewhere, and when there is no collision, it is necessary to choose a threshold so that all spaces are within the threshold. be. Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, if the central device 32 has a means for detecting the length of a collision or space over, it is possible to calculate the corrected control time instead of the amount of change in the control time in each concentrator/distributor 33. Time itself can also be used as a control signal. In addition, in the embodiment, as such a control signal, 2
Although more than one bit is used, it is also possible to allocate only one bit to the control signal and send it out multiple times. For example, if the possible range of the inter-word time Sij is -16 to 16, the predetermined control signal can be sent in six frame times including the synchronization bit accompanying control signal sending. Furthermore, when only the amount of change is to be transmitted, it can be sent in three frame times. Although the line concentrator and distributor is configured to concentrate and distribute information from a plurality of terminals, the present invention can be treated as having the line concentrator and distributor function as a buffer for inputting and outputting information from one terminal. Although the embodiments of the present invention have been described above in detail, the present invention is not limited to these embodiments in any way. For example, the concentrating transmission line and the distribution transmission line do not necessarily have to be independent transmission lines, and one transmission line may be used by dividing the band. Furthermore, the signals may be conveyed on the pair of transmission paths in any form. The exchange control 51 may use any processing method. For example, the distribution circuit 75 may be of an unnecessary type, or the exchange control section 51 may have multiplexing capability. It goes without saying that the exchange always holds subscriber data. That is, the state in which the line concentrator and distribution device and the terminal equipment are connected to the transmission path is held as information. Then, if the connection status changes, the subscriber data is also updated. The invention may essentially only be applied when changing this subscriber data. Furthermore, it would be more correct to view this invention as a network system centered on a central device with exchange functionality.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one system of the line concentration and distribution method, FIG. 2 is a diagram showing signals in the system related to the line concentration and distribution method shown in FIG. 1, and FIG.
FIGS. 4 to 15 are diagrams showing the configuration of the system of one embodiment, and are diagrams for explaining the system shown in FIG. 3 in detail. FIG. 4 is a diagram showing the configuration of the central device, and FIG. 5, 8, and 9 are diagrams showing signals on the transmission path, Figures 6 and 7 are diagrams for explaining the configurations of the collision detection circuit and the space over detection circuit, and Figure 10 is a diagram showing the configuration of the collision detection circuit and the space over detection circuit. , FIG. 11 is a diagram for explaining the processing operation in this system, FIG. 12 is a diagram showing the configuration of one of the signal transmission time control circuits, and FIG. 13 is a diagram showing the configuration of the line concentration distribution device. , a diagram showing the configuration of the control signal generation circuit, FIG. 14, and FIG.
FIG. 5 is a diagram for explaining the multiplexing circuit in the central device, FIG. 14 is a diagram showing its configuration, and FIG. 15 is a diagram showing waveform diagrams of signals in each part thereof. 32...Central device, 33...Line concentration distribution device, 3
5...Terminal, 37, 39...Transmission line, 45...Collision detection circuit, 49...Control signal generation circuit, 83...
...Control signal detection circuit, 89...Signal sending time control circuit.

Claims (1)

[Claims] 1. Signals from a plurality of line concentration distribution terminals are time-divisionally transmitted to a central device on a first transmission path, and signals generated from this central device are time-divisionally transmitted to a second transmission path. The central device includes a detecting means for detecting a collision between signals from the concentrating and distributing terminals, and a detection means for detecting a collision between signals from the concentrating and distributing terminals, and arithmetic means for generating a control signal to be sent to a line concentration and distribution terminal, and the line concentration and distribution terminal is characterized in that it has a control means for controlling the timing of sending a signal to the central device based on the control signal. Concentration distribution method. 2. The control means includes means for detecting the control means from the central device, and means for delaying the signal to the central device by a predetermined time according to the control signal obtained by the detecting means and sending it to the first transmission path. A line concentration and distribution system according to claim 1, characterized in that it is comprised of: 3. The line concentration and distribution system according to claim 1, wherein the control signal carries an amount of change in the timing of transmitting the signal from the line concentration and distribution terminal to the central device. 4. The line concentration and distribution system according to claim 1, wherein the control signal carries a value indicating the timing at which the signal is sent from the line concentration and distribution terminal to the central device. 5. A patent claim characterized in that the calculation means calculates a control signal to a concentrator and distribution terminal that has generated a temporally later signal in a frame when time-division multiplexing is performed, of the two signals involved in the collision. The line concentration and distribution method described in item 1. 6. A patent characterized in that the calculation means calculates a control signal to be sent to the concentrator and distribution terminal that generated the temporally earlier signal in the frame when time-division multiplexing is performed, of the two signals involved in the collision. A line concentration distribution system according to claim 1. 7. The line concentration distribution system according to claim 1, wherein the detection means includes means for measuring the length of signal collision. 8. The line concentrator according to claim 1, wherein the central device fixes the sending order of the time-division multiplexed signals when time-division multiplexing the signals and sending them out onto the second transmission path. Distribution method. 9. Signals from a plurality of line concentration distribution terminals are placed on a first transmission path in a time-division manner and sent to the central device, and signals generated from this central device are placed on a second transmission path in a time-division manner to transmit the signals to the plurality of A line concentration and distribution system for sending signals to line concentration and distribution terminals, wherein the central device includes means for detecting a space between signals from the terminals, means for comparing the space detected by the means with a predetermined value, and the means for detecting a space between signals from the terminals. a calculation means that generates a control signal when the space is detected to be equal to or greater than a predetermined value, and the line concentration distribution terminal controls the timing of sending the signal to the central device based on the control signal. A line concentration distribution method characterized by having a means.