JPH0586716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a PB dial sending device in a time division exchange.

[Technical background of the invention and its problems] In a conventional PB dial sending device, a telephone is connected to a line circuit, and the line circuit and trunk circuit are connected to a receiving highway and a transmitting highway, respectively. A time division switch circuit is connected to connect the highways, and a central office line is further connected to the trunk circuit. Traditionally, line circuits and trunk circuits have been connected to the receiving highway and the transmitting highway through two transmission paths, and the two transmission paths within the line circuit and trunk circuit have been connected to one transmission path via a hybrid circuit. I switched it to connect to a telephone or central office line. In such a configuration, PB
When a dial is transmitted from the telephone, this PB dial signal is first input to the line circuit, and this signal output from the line circuit is input to the time division switch circuit via the reception highway, and then from the time division switch circuit to the transmission highway. is input to the trunk circuit via. Finally, the PB dial signal is output from the trunk circuit to the central office line.

On the other hand, the hybrid circuit in the trunk circuit is
Although the configuration is such that the PB dial signal input to the trunk circuit is output only to the office line, there is a problem in that the same PB dial signal flows from within the trunk circuit to the receiving highway. Therefore, the PB dial signal that flows into the receiving highway flows through the transmitting highway via the time division switch circuit, and is sent back to the transmitting telephone via the line circuit.

In order to prevent the PB dial signal from being transmitted from the trunk circuit to the subscriber, the time division switch circuit is disconnected and a state in which no signal is transmitted to the subscriber, that is, silence is sent out. Ta. In conventional PB dial sending devices, the timing of disconnection of the time division switch circuit must be controlled while monitoring the PB dial signal output from the line circuit, making control complicated. especially
In an exchange system that has distributed functions such as a PB dial sending processor and a call path control processor, at what timing does the PB dial sending processor send out a PB dial signal, and based on this sending timing, the call path control processor In order to execute a series of operations to determine the disconnection timing of the time division switch, control information must be exchanged between the PB dial sending processor and the communication path control processor, which creates a problem of complicated control. Ta. In addition, there are usually multiple line circuits and trunk circuits,
It is difficult to simultaneously perform the above-mentioned complex control for both line circuits and trunk circuits.
The reduction in processing capacity was unavoidable.

[Object of the Invention] The present invention eliminates the above-mentioned drawbacks, does not reduce processing capacity, effectively sends a PB dial signal to a central office line with simple control, and does not require the subscriber to be surrounded when sending the PB dial signal. An object of the present invention is to provide a PB dial sending device capable of sending out a silent PCM signal without returning the PB dial signal that has been read.

[Summary of the Invention] The present invention includes a line circuit connected to a telephone set, a time division switch unit that transmits signals in a time division manner via a transmission line connected to the line circuit, and a time division switch unit connected to the transmission line and transmitting signals via a transmission line connected to the line circuit. An electronic exchange equipped with a trunk circuit that transmits information to central office lines and a control unit that controls these circuits,
Based on the PB dial signal generation means that generates the PB dial signal and the control signal output from the control section, when the trunk circuit sends out the PB dial signal generated from the PB dial signal generation means to the central office line, The present invention is characterized by comprising a signal transmission stop means provided in a trunk circuit for stopping signal transmission to a transmission path.

[Embodiments of the invention] FIG. 1 is a schematic configuration diagram of a time division switch.
CC is the central control unit, TS is the time division switch circuit,
CL is the control line, HR is the PCM reception highway,
HT is the PCM transmission highway, PB is the PCM push button dial generator, and HP is the PCMPB transmission highway. The PBPCM push button dial generator may be provided within the line circuit or may be provided commonly within the HTPCM transmission highway, but in this embodiment, it is provided separately from the TS time division switch circuit. .

L0 is a line circuit, which is composed of an LC0 telephone interface, an LH0 hybrid circuit, an LA0PCM codec, an LP0 line control circuit, and an LS0PCM highway selector circuit. If there is no need to send a PB pushbutton signal to the telephone, the LS0PCM highway selector circuit in the line circuit is not required.

T0 is a trunk circuit, and its configuration is TC0
It consists of a central office line interface circuit, a TH0 hybrid circuit, a TA0PCM codec, a TP0 trunk control circuit, and a TS0PCM highway selector circuit.

An embodiment in which a subscriber performs abbreviated dialing service on a central office line and sends a PB dial to the central office line will be described with reference to FIG. When a subscriber picks up the handset of a telephone connected to the LL0 telephone line connected to the L0 line circuit, the current flowing through the LL0 telephone line changes, so this current is detected by the LC0 telephone interface circuit and the LP
A signal is sent to the 0 line control circuit to detect the calling state, and the calling information is transmitted from the LP0 line control circuit to the CC central control circuit via the CL control line.

The CC central controller learns that the L0 line circuit has made a call, and sends a signal from the L0 line circuit to the RG transmission register, connects the communication path between the L0 line circuit and the RG reception register, and sends a signal to the L0 line circuit.
The TS time division switch circuit sends out a dial tone, usually called "two", to indicate that it is OK to input a dial signal from the telephone via the HTPCM transmission highway. When a speed dial signal is input from the telephone to the L0 line circuit through the LL0 telephone line, the speed dial signal is input to the LH0 hybrid circuit through the LC0 telephone interface circuit. LH0 hybrid circuit
The signal from the LA0PCM codec is routed to the LC0 telephone interface circuit, and vice versa.
The function is to separate the signal output from the 0 telephone interface circuit and send it to the HRPCM reception highway via the LA 0 PCM codec. Here, the analog speed dial signal output from the LH0 hybrid circuit is LA0PCM
A codec converts it into a digital speed dial signal. This speed dial signal is output to the HRPCM reception highway, via the TS time division switch, and input to the RG transmission register through the HTPCM transmission highway. When the RG transmission register receives the code of the speed dial signal, it notifies the CC central controller of the speed dial information via the CL control line. The CC central controller disconnects the communication path between the L0 line circuit and the RG transmission register,
Block the T0 trunk circuit and connect the L0 line circuit and T
Connect the communication path of the 0 trunk circuit.

The CC central controller connects the T0 trunk circuit and the L0 line circuit, translates the speed dial after a certain period of time, transmits this to the PBPCM push button dial generator, and controls the CL to send a PB dial request to the T0 trunk circuit. Send it out via the line.

When the TP0 trunk control circuit in the T0 trunk circuit receives a PB dial sending request from the CC central controller, it sends silence from the T0 trunk circuit to the L0 line circuit.
By placing the TA0 PCM codec in standby mode, a silent PCM signal is sent to the L0 line circuit.

Here, standby mode means that the TA0PCM codec does not operate (the output signal from the normal TH0 hybrid circuit is not transmitted from the TA0PCM codec).
Indicates the mode (not output to HR reception highway). The easiest way to achieve this is TA0
The idea is to reduce the supply voltage to the PCM codec. There is no particular limitation on the method of achieving this.

Here, the operation of the T0 trunk circuit when receiving a PB dial sending request from the CC central controller will be explained. For a request to send a PB dial to the T0 trunk circuit, the CC central controller simply sends a signal via the CL control line to the T0 trunk circuit, and the T0 trunk circuit handles all the rest. In other words, the CC central control device is no longer involved in these processes after sending out the PB dial sending request. This makes it possible to simplify control without reducing the overall processing capacity of the PB dial sending device.

TP0 trunk control circuit from CC central controller
When a PB dial transmission request is received, the TA0PCM codec is placed in standby mode. When the TA0PCM codec is set to this mode, the output signal from the TH0 hybrid circuit to the TA0PCM codec is cut off on the TA0PCM codec side.
The TP0 trunk control circuit also connects the HPPCMPB sending highway to the TS0PCM highway selector circuit by switching in order to accept the PB dial signal from the HPPCMPB sending highway to the TS0PCM highway selector circuit. TP0 trunk control circuit Specifies the PCM channel (channel) of the PB dial signal to be sent to the T0 trunk circuit for the TA0PCM codec. The PB dial signal generated from the PBPCM push button dial generator is
TS0PCM via HPPCMPB transmission highway
Input to the highway selector circuit. This input PB dial signal passes through the TA0PCM codec and the TH0 hybrid circuit.
Output from the TC0 station line interface to the TT0 station line. Of course, this PB dial signal is
Even if the TH0 hybrid circuit is enclosed in the TA0PCM codec, the TA0PCM codec blocks this PB dial signal, so the L
There is no leakage to the 0 line circuit side. And TA0
A silent state with no signal flowing from the PCM codec to the HR reception highway is transmitted via the HR reception highway from the TS time division switch circuit to the HT transmission highway to the L0 line circuit, and the LL0 telephone line has no signal. state. When the PB dial transmission is completed, the TP0 trunk control circuit sends the audible tone transmitted from the central office line to the subscriber via the L0 line circuit.
It moves the codec from standby mode to active mode, returns the TS0PCM highway selector circuit from the HPPCMPB transmission highway to the HTPCM transmission highway, and returns the TA0PCM codec to the original PCM
Specify the channel.

As a result, while the PB dial is being sent, silence is sent to the subscriber from the PCM codec, and after the dial pulse is sent, the subscriber can hear audible sound from the central office line. The above-mentioned PB dial sending device can easily prevent PB dials from being encircled by subscribers when sending PB dials.

[Effects of the Invention] In the above PB dial sending device, when sending a PB dial, the TS time division switch circuit is not controlled by the CC central controller, so the processing capacity of the CC central controller is increased, and the PB dial can be sent in a simple manner. When sending to the line and sending PB dial, it is possible to send silence to the subscriber. In addition, the CC central controller does not need to control the TS time division switch circuit when sending out the PB dial, and only needs to issue a dial sending request to the T0 trunk circuit, allowing effective functional distribution.

Furthermore, the present invention is not limited to the above embodiments. For example, the standby mode and active mode may be set not only by power control but also by circuitry. Also, this mode setting is
The target is not limited to only codecs.
In short, all that is required is to generate a silent PCM signal to the subscriber.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. L0, L1...Line circuit, LC0...Telephone interface circuit, LH0...Hybrid circuit, LA0...PCM codec, LP0...Line control circuit, LL0...Telephone line, LS0...
PCM highway selector circuit, T0, T1...
Trunk circuit, TC0...Station line interface circuit, TH0...Hybrid circuit, TA0...
PCM codec, TP0... line control circuit,
TT0...Station line, TS0...PCM highway selector circuit, CC...Central control unit, TS...Time division switch circuit, CL...Control line, HR...
PCM reception highway, HT...PCM transmission highway, HP...PCM PB transmission highway, PB...
...PCM push button dial generator, RG...outgoing register.

Claims (1)

[Claims] 1. A line circuit connected to the telephone, a time division switch unit that transmits signals in a time division manner via a transmission line connected to the line circuit, and a time division switch unit connected to the transmission line and transmits the signal to the central office line. An electronic exchange equipped with a trunk circuit and a control section for controlling these circuits, which operates based on information from the telephone set.
Based on a PB dial signal generating means for generating a PB dial signal and a control signal output from the control section, the trunk circuit sends the PB dial signal generated from the PB dial signal generating means to the central office line. 1. A PB dial sending device comprising: a signal sending stop means provided in said trunk circuit that stops sending a signal from said trunk circuit to said transmission path when said PB dial sending device.