JPS6367387B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a digital terminal, and more particularly to a data information transmission system that enables data information transmitted from a data terminal or the like to be transmitted via a digital trunk line.

(b) Background of the Technology In a digital trunk line for multiplex transmission of audio signals, each digital signal is composed of 8 bits per predetermined period (for example, 8 kilohertz). When automatic exchanges are connected to each other by such a digital trunk line, in order to transmit the connection status to the opposite automatic exchange, the automatic exchange uses a predetermined position in the 8 bits every predetermined frame period (for example, 6 frame periods). So-called bit stealing is performed using one bit of the data. Furthermore, in some digital trunk lines, when a predetermined number (for example, 15 bits) or more of the transmitted bits consecutively have a logic value of 0, the first bit of the predetermined number is forcibly set to a logic value of 1. It may have an all-zero prohibition function. This type of bit steal function and all zero prohibition function have almost no effect on the audio signals transmitted by each channel, but have a non-negligible effect when data is transmitted by each channel.

(c) Prior Art and Problems FIG. 1 is a diagram showing an example of a conventional data information transmission system, and FIG. 2 is a diagram showing an example of data information of the digital trunk line in FIG. 1. In Figure 1, the data terminal DTE is connected to the data service unit DSU and the digital subscriber circuit in the network NW of the digital exchange.
Via the DLC, digital trunk lines L1 and L2 are accommodated via digital terminals DT1 and DT2, respectively. data terminal
The DTE connects to the network NW via the data service unit DSU and the digital subscriber circuit DLC.
The data information transmitted and received by
Bits b1 to b6 are used as data bits D0 to D5 to transmit data to the opposite data terminal DTE, and bit b7 is used as a terminal signal bit S to transmit the state of the data terminal DTE to the opposite data terminal DTE. The remaining bit b0 is not particularly used. Such data terminal
When the DTE is connected to the channel CH of the digital trunk line L1 or L2 via the network NW, the data information transmitted by each channel CH of the digital trunk line L1 or L2 becomes as shown in FIG. Note that the digital trunk line steals bit b7 of each channel CH every six frame periods in order to transmit and receive exchange signal bit e between opposing digital exchanges. Such bit steal is data bit D0 of each channel CH.
Although it has no effect on D5 to D5, it does affect the terminal signal bit S transmitted and received by the data terminal DTE. Furthermore, the digital trunk line L2 has a function of inhibiting all 0 bits for 15 consecutive bits. The above-mentioned 0 prohibition function is the data bit D5.
may affect.

As is clear from the above explanation, in a conventional data information transmission system, the digital trunk line L1
The bit steal function provided by L2 may cause an error in the terminal signal (bit S) transmitted and received by the data terminal DTE, and the all zero prohibition function provided by the digital trunk line L2 may cause an error in the data (bit S) transmitted and received by the data terminal DTE. It was not possible to transmit the data information over the digital trunks L1 and L2 because of the risk of errors in bit D5).

(d) Purpose of the Invention The purpose of the present invention is to eliminate the drawbacks of the conventional data information transmission method as described above, and to realize a means for eliminating the influence on data information by the bit steal function and all zero prohibition function. The object of the present invention is to enable data information to be transmitted over digital trunk lines.

(e) Structure of the Invention The object of the present invention is to provide a digital terminal that connects a digital trunk line and a digital switch that steal bits at a first predetermined position of data information transmitted by each channel at a predetermined frame period. a conversion means for exchanging a signal bit at a second predetermined position of the data information sent by the digital exchange with a bit at the first predetermined position and sending it to the channel; and data arriving from each channel of the digital trunk line. means for reproducing the signal bits by integrating the bits at the first predetermined positions of the information; and the bits at the first and second predetermined positions of the data information including the signal bits reproduced by the means. This is accomplished by providing means for exchanging the information and sending it to the digital exchange.

(f) Embodiment of the invention An embodiment of the invention will be described below with reference to the drawings. FIG. 3 is a diagram showing a data information transmission system according to an embodiment of the present invention, and FIGS. 4 and 5 are diagrams showing an example of data information of the digital trunk line in FIG. 3. Note that the same reference numerals indicate the same objects throughout the figures. Also, in Figure 3,
Only the network NW of the digital exchange and the digital terminals DT1 and DT2 connecting the digital trunk lines L1 and L2, respectively, are shown, and the data terminal DTE, data service unit DSU and digital subscriber circuit DLC are shown.
is omitted. In FIG. 3, the digital terminal DT1 includes an insertion circuit I that steals the exchange signal bit e1 transmitted from the network NW to bit b7 of each channel CH;
An extraction circuit R is provided for extracting the exchange signal bit e2 arriving from the digital trunk line L1 by stealing bit b7 of each channel CH. The data information transmitted from the data terminal DTE (not shown) to the network NW via the data service unit DSU and the digital subscriber circuit DLC is almost the same as in FIG. 1, except that the terminal signal bit S is bit b0. placed in
Bit b7 is not used for transmission between data terminals DTE and is always set to logic 1. The data information sent to the digital trunk line L1 is also substantially the same as that in FIG. 2, as shown in FIG. 4, except for bits b0 and b7. Therefore, bit stealing by the insertion circuit I and the extraction circuit R in the digital terminal DT1 does not affect the terminal signal bits S at all, rather than affecting the data bits D0 to D5. Furthermore, in addition to the insertion circuit I and the extraction circuit R, the digital terminal DT2 includes conversion circuits CH1 and CH2,
An integrating circuit INT is provided. Conversion circuit CH
1 exchanges bits b0 and b7 of the data information as described above transmitted from the network NW and transmits it to the insertion circuit I. The insertion circuit I steals the exchange signal bit e1 in the same way as in the digital terminal DT1, and then sends it to the digital trunk line L2. As a result, digital relay line L
The data information sent to bit 2, as shown in FIG. 5, is the same as in FIG. 2, except that bit b0 is always set to a logic value of 1. As a result, bit b0 with logical value 1 is transmitted at least every 8 bits, so
The all-zero prohibition function is not activated and there is no risk that the data bits D0 to D5 and the terminal signal bit S will be forcibly set to a logic value of 1, but the terminal signal bit S will be set to 6 as in FIG. There is a risk of being affected by bit stealing every frame period. On the other hand, each channel CH of digital relay line L2
The data information arriving from is also the same as in Figure 5,
The terminal signal bit S may be affected by bit stealing every six frame periods. The extraction circuit R steals the exchange signal bit e2 in the same way as in the digital terminal DT1, and then transmits it to the integration circuit INT. Integrating circuit INT is
Bit b7 of each channel CH transmitted 3 consecutively
A majority vote is taken for each frame, and the logic value of the terminal signal bit S is determined and transmitted to the conversion circuit CH2. Conversion circuit CH2 converts each channel in reverse to conversion circuit CH1.
Bits b0 and b7 of the CH data information are exchanged and sent to the network NW. As a result, the influence of the bit steal function on terminal signal bit S is removed, and furthermore, terminal signal bit S is added to bit b0.
is placed and sent to the network NW.

As is clear from the above description, according to this embodiment, bit b0 of data information is transferred to digital trunk line L1 having only a bit steal function.
By arranging the terminal signal bit S in The influence on data information is removed by exchanging bits b0 and b7 and extracting terminal signal bit S by the integrating circuit INT.

Note that FIGS. 3 to 5 are only one embodiment of the present invention, and for example, a digital terminal DT
The configurations of DT 1 and DT 2 are not limited to those shown in the drawings, and many other modifications may be considered, but the effects of the present invention will not change in any case. Furthermore, the data information of each channel CH is not limited to what is shown in the figure, and many other modifications may be considered, but the effects of the present invention remain the same in any case.

(g) Effects of the Invention As described above, according to the present invention, in the digital terminal, it is possible to remove the influence on data information by the bit steal function and all zero prohibition function, and the data information can be transmitted through the digital trunk line. becomes.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a conventional data information transmission method, FIG. 2 is a diagram showing an example of data information on the digital trunk line in FIG. 1, and FIG. 3 is a diagram showing an example of data information transmission according to an embodiment of the present invention. A diagram showing the method,
Figures 4 and 5 are diagrams showing examples of data information of the digital relay line in Figure 3, where Figure 4 is a diagram of a digital relay line that does not have an all-zero prohibition function, and Figure 5 is a diagram of a digital relay line that does not have an all-zero prohibition function. 1 shows a diagram of a digital trunk line with functions; FIG. In the figure, b0 to b7 are bits, CH is a channel, CH1 and CH2 are conversion circuits, D0 to D5 are data bits, DLC is a digital subscriber circuit, DSU is a data service unit, and DT1
and DT2 are digital terminals, DTE is a data terminal, e, e1 and e2 are exchange signal bits, I is an insertion circuit, INT is an integration circuit, L1 and L2 are digital trunk lines, NW is a network, R is an extraction circuit, and S indicates the terminal signal bit.

Claims (1)

[Claims] 1. In a digital terminal connecting a digital switch and a digital trunk line that steals bits at a first predetermined position of data information transmitted by each channel at a predetermined frame period, the first bit of the data information transmitted by the digital switch is converting means for exchanging the signal bits at the second predetermined position with the bits at the first predetermined position and transmitting the same to the channel; means for reproducing the signal bits by integrating the bits; and bits at the first and second predetermined positions of the data information including the signal bits reproduced by the means are exchanged and sent to the digital exchange. 1. A data information transmission method comprising: means.