JPH05103114A - Multiplexer - Google Patents

Abstract

PURPOSE:To select a reset operation so that a start may not be performed by not making the start by performing a blocking for the switchboard on the side of callers at the time of the rise of power source or in a control reset and transmitting the same signals as non-calling state for the switchboard on the side of non-callers, in a multiplexer in which a pulse code modulation is performed for a switchboard signal and a voice signal and the code is multiplexed to plural channels. CONSTITUTION:By a reset selection circuit composed of AND gates 15, 16 and input terminals 18 to 20, 3 state buffers 12 are made disable in the reset for the switchboard on the side of a caller and 3 state buffers 11 are made disable in the reset for the switchboard on the side of a non-caller, respectively. Thus, the control of grounding or non-grounding is performed for a switchboard control line 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex converter for pulse-code modulating an exchange signal and a voice signal to multiple-channel multiplex, and more particularly to a multiplex converter having an E-line control circuit connected to an E & M signal type switch trunk. Regarding

[0002]

2. Description of the Related Art In a conventional multiplexer / conversion device, an E-line control circuit connected to a switching system has a terminal 33 as shown in FIG.
Due to the reset input from, the transistors 24 and 25 connected in Darlington become non-conductive (off), so that terminal 2
The exchange control line (E line) of No. 1 was not grounded.

[0003]

In the E-line control circuit of the above-mentioned conventional multiplex converter, the exchange control line (E line) due to reset is fixed to the non-ground. Generally, in the case of the E & M signal system of the telephone line, the E line is not grounded when no call is made, and the E line is grounded when the call is made. Therefore, the call can be accepted from the exchange on the calling side. In such a situation, there is a problem that the calling side exchange operates to activate toward the called side exchange when the subscriber lifts the handset.

[0004]

SUMMARY OF THE INVENTION A multiplexer / converter of the present invention is a multiplexer / converter for pulse-code-modulating an exchange signal and a voice signal to multiplex them. A first AND gate to be input, a second AND gate to which the reset signal and the output trunk selection signal are input, and a second gate for controlling an E line control signal by the output of the second AND gate A circuit, a first gate circuit for controlling the output of the second gate circuit by the output of the first AND gate, and the output of the first gate circuit grounds or ungrounds the control line to the exchange. And a controlling transistor.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

In this embodiment, an exchange control line 1 connected to an E line of an E & M signaling type exchange trunk, a diode 2 having a cathode connected to the exchange control line 1, and a Darlington-connected collector whose anode is a diode 2 are connected. And transistors 3 and 4 whose emitters are connected to ground 5,
A first resistor 6 connected between the −5V power source and the base of the transistor 4 in Darlington connection, and a second resistor 7 and a third resistor 8 connected in series between the base of the transistor 4 and the + 5V power source. , The output is connected to the connection point of the second resistor 7 and the third resistor 8, the input is connected to the ground 14 via the fourth resistor 13, and the enable terminal is the reset input and the input trunk (ICT) selection. A first 3-state buffer 11 connected to the output of the AND gate 15 to which a signal is input, an output connected to the input of the first 3-state buffer 11, an input connected to the E-line control input 17,
Enable terminal is reset input and output trunk (OGT)
The second 3-state buffer 12 connected to the output of the AND gate 16 to which the selection signal is input.

Next, the operation of this embodiment will be described. By the reset selection circuit composed of AND gates 15 and 16 and the input terminals 18 to 20, the enable terminal of the 3-state buffer 12 is used for the reset of the calling side switch, and the 3-state is used for the reset of the non-call side switch. The enable terminals of the buffer 11 are disabled. The output of the 3-state buffer 11 in each case is grounded and ungrounded, and the grounding circuit formed by the level conversion circuit formed by the resistors 6 to 8 and the transistors 3 and 4 connected in Darlington and the reverse current prevention diode 2 are formed. The switch control line 1 is controlled to be grounded or non-grounded by.

[0008]

As described above, the present invention is connected to the AND gate for setting the control line to the ground at the time of resetting when connected to the switch of the calling party, the three-state buffer, and the switch of the non-caller side. In the case of a reset, the control line is not grounded at the time of resetting, and by having a 3-state buffer, it is possible to prohibit the switching operation on the calling side from the activation operation when the subscriber lifts the handset. effective.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of an example of a conventional multiplex conversion device.

[Explanation of symbols]

 1,21 Exchange control line (E line) 2,22 Diode 3,4,23,24 Transistor 11,12,31 Three-state buffer 15,16 AND gate 17,32 E line control signal (negative logic) 18,33 Reset Signal 19 Incoming trunk selection signal 20 Outgoing trunk selection signal

Claims (1)

[Claims] 1. A multiplex converter for pulse-code-modulating an exchange signal and a voice signal to multiplex, and a first AND gate to which a reset signal at power-on and an incoming trunk selection signal are inputted, and the reset signal. And an output trunk selection signal are input to the second AND gate, a second gate circuit for controlling the E-line control signal by the output of the second AND gate, and the output of the second gate circuit. A multiplex conversion having a first gate circuit controlled by the output of the first AND gate and a transistor for controlling the control line to the exchange to be grounded or ungrounded by the output of the first gate circuit. apparatus.