JPH077990B2 - Select signal transmitter / receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to transmission and reception of a selection signal in a subscriber line empty service of a telephone exchange.

(Prior Art) FIG. 2 is a block diagram showing a conventional selection signal transmission / reception system, in which 21 is a subscriber line exchange, 22a and 22b are subscriber lines, and 2 is a subscriber line.
3 is a telephone, 24 is an in-office device, 25 is a home device, 241, 251 are detection circuits for determining the status of subscriber lines, 242, 252 are relays, 2
42a, 242b, 252a, 252b are relay contacts, 243, 253, 257 are amplifiers, 245 is PB signal receiving circuit (hereinafter referred to as PBR), 254 is P
B signal oscillator (hereinafter referred to as PBOSC), 255 is a key (hereinafter referred to as K
EY), 258 is a speaker, 461 to 46n are analog signal input terminals, and 244 is a selector that selects and outputs one of the input terminals 461 to 46n.

The in-station equipment is a subscriber line 22 of the subscriber line exchange 21 in the exchange.
a and 22b are connected in parallel, and the in-home device 25 is connected to the subscriber lines 22a and 22b.
It is connected in parallel with the telephone 23 connected via.

When the detection circuit 241 detects that the subscriber lines 22a, 22b are empty, the relay 242 operates, the contacts 242a, 242b of the relay are closed, and the amplifier 243 is connected to the subscriber lines 22a, 22b. Terminal 46
One of the unillustrated analog signal sources (hereinafter referred to as sound source) connected to 1 to 46n is the selector 244.
Is sent to the subscriber lines 22a, 22b via the amplifier 243 and relay contacts 242a, 242b. The sound source transmitted to the subscriber lines 22a and 22b is input to the home device 25, amplified by the amplifier 257 via the detection circuit 251, and output to the speaker 258.

When the subscriber selects another sound source, the subscriber presses a desired numeric key of KEY 255. The operation will be described below. However, the relays 242 and 252 are operated by the detection circuits 241 and 251 when the subscriber lines 22a and 22b are empty.

When the KEY 255 is pressed, the PBOSC 254 oscillates at a combination of frequencies corresponding to the pressed key, is amplified by the amplifier 253, and is sent to the in-office device 24 via the contacts 252a and 252b. Station device 2
The PB signal input to 4 is input to and received by the PBR 245 via the detection circuit 241 and is held in a register (not shown) in the selector 244. Depending on the contents of the register, the terminals 461 to 46n
One sound source is selected from the sound sources of.

(Problems to be Solved by the Invention) The conventional selection signal transmitting / receiving system has been described above, but has the following problems. That is, since the PB signal uses a signal in the voice band, the PBR is designed to be hard to operate by voice. On the other hand, PBR has a characteristic that it is difficult to operate when a PB signal is input at the same time as a voice signal or the like. Therefore, since the sound source transmitted to the subscriber lines 22a and 22b is always input to the PBR 245 via the detection circuit 241, the PBR 245 may malfunction due to the sound source even when there is no PB signal. Also, since the PB signal and the sound source are simultaneously input to the PBR245 while the PB signal is being transmitted from the home device 25 by pressing the KEY255, there is a possibility that the PB signal cannot be received, and there is a drawback that stable sound source switching cannot be performed. .

The present invention has been made to eliminate such drawbacks, and an object of the present invention is to provide a selection signal transmitting / receiving system capable of stable sound source switching.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a PB that oscillates a PB signal according to the operation of the subscriber and outputs the PB signal to the subscriber line.
The voltage difference between the signal oscillating circuit and the high resistance loop is closed to the subscriber line via the high resistance when the PB signal is output from the PB signal oscillating circuit to the subscriber line by the operation of the subscriber. An in-home device having a first connecting means for generating a signal, and a detection connected to the subscriber line to determine whether or not there is an empty line in the subscriber line and a state of a voltage difference on the subscriber line. A circuit, a selector circuit for inputting a plurality of analog signals, selecting one signal from the plurality of analog signals corresponding to the PB signals received by the PB signal receiving circuit, and outputting the selected signal to the subscriber line; When the detection circuit detects that the subscriber line is empty, the output from the selector circuit is connected to the subscriber line,
A select signal transmitting / receiving circuit is provided with an intra-station device having a second connecting means for disconnecting the output from the selector circuit from the subscriber line when it is detected that the voltage difference on the subscriber line has changed. It is a thing.

(Operation) When switching channels with PB signal transmission in the subscriber line empty service, a high resistance loop is created when the PB signal is transmitted, and when the high resistance loop is detected by the station device, the sound source transmission is stopped and the PBR is connected. . As a result, stable selection signals are exchanged.

Therefore, the above problems can be eliminated.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 11 is a subscriber line exchange, 12a and 12b are subscriber lines, 13 is a telephone, 14 is a local device, 15 is a home device, and 141 and 151 are subscribers. Detection circuit for determining the state of the main line, 142, 152, 156 are relays, 142a, 142b, 1
52a, 152b, 156a are relay contacts, 143, 153, 157 are amplifiers,
145 is a PB signal receiving circuit (hereinafter referred to as PBR), 154 is a PB signal oscillation circuit (hereinafter referred to as PBOSC), and 155 is a keypad (hereinafter referred to as KE).
Y)), 158 is a speaker, 159 is a resistor, 461 to 46n are analog signal input terminals, and 144 is the input terminals 461 to 46n.
The selectors that select and output one more are shown.

The in-station device is a subscriber line 12 of the subscriber line exchange 11 in the exchange.
a, 12b are connected in parallel, and the in-home device 15 is a subscriber line 12a, 12b.
It is connected in parallel with the telephone set 13 connected via.

When the detection circuit 141 detects that the subscriber lines 12a and 12b are empty, the relay 142 operates, the contacts 142a and 142b of the relay are closed, and the amplifier 143 is connected to the subscriber lines 12a and 12b. Terminal 46
One of the unillustrated analog signal sources (hereinafter referred to as sound source) connected to 1 to 46n is the selector 144.
It is sent to the subscriber lines 12a and 12b via the amplifier 143 and relay contacts 142a and 142b. The sound source transmitted to the subscriber lines 12a and 12b is input to the home device 15, is amplified by the amplifier 157 via the detection circuit 151, and is output to the speaker 158. When the subscriber selects another sound source, the subscriber presses a desired numeral key of the KEY 155, and the operation will be described below. However, when the subscriber lines 12a and 12b are empty, the relays 142 and 152 are operated by the detection circuits 141 and 151. When the KEY 155 is pressed, the PBOSC 154 oscillates at a combination of frequencies corresponding to the pressed key, is amplified by the amplifier 153, and is sent to the in-office device 14 via the contacts 152a and 152b. The PB signal input to the in-station device 14 is input to the PBR 145 via the detection circuit 141, received, and held in a register (not shown) in the selector 144, and the sound source of the terminals 461 to 46n is stored according to the contents of the register. One more sound source is selected by the selector 144. When the KEY 155 is pressed, the relay 156 is operated by its common contact, and the contact 156a closes a loop (high resistance loop) between the subscriber lines 12a and 12b via the resistor 159. Subscriber line by the high resistance loop
A change occurs in the voltage difference between 12a and 12b, and the change is detected by the detection circuit 14
1, the relay 142 is restored and the contacts 142a and 142b are opened, so that the sound source transmission from the in-station device is stopped and the switch (not shown) in the detection circuit 141 is closed,
AC signals on the subscriber lines 12a and 12b are transmitted to the PBR 145.

(Effects of the Invention) As described above, according to the present invention, while the PB signal is being transmitted, the sound source being transmitted from the in-station device is stopped, and the PBR signal is connected only during that period, so stable transmission and reception of the selection signal Can be expected.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional selection signal transmitting / receiving system. 11 …… Subscriber line switch, 12a, 12b …… Subscriber line, 13 ……
Telephone, 14 ... In-house device, 15 ... Home device, 141, 151 ...
… Detection circuit, 142,152,156 …… Relay, 142a, 142b, 152a,
152b, 156a …… Relay contact, 143,153,157 …… Amplifier, 14
4 …… Selector, 145 …… PB signal receiving circuit, 154 …… PB signal oscillating circuit, 155 …… Electronic key, 158 …… Speaker, 159 ……
resistance.

Claims (1)

[Claims] 1. A PB signal oscillating circuit for oscillating a PB signal according to an operation of a subscriber and outputting the PB signal to a subscriber line, and a PB signal oscillating circuit from the PB signal oscillator circuit to the subscriber line by an operation of the subscriber. An in-home device having a first connecting means for generating a voltage difference by closing a high resistance loop in the subscriber line via a high resistance when outputting a signal; and a home device connected to the subscriber line, A detection circuit for determining whether the subscriber line is empty or not and the voltage difference state of the subscriber line, and receiving the PB signal sent to the subscriber line via the detection circuit. PB signal receiving circuit and a selector for selecting one signal from the plurality of analog signals corresponding to the PB signal received by the PB signal receiving circuit and outputting the analog signal to the subscriber line Circuit and the detection circuit When it is detected that the subscriber line is empty, the output from the selector circuit is connected to the subscriber line, and when the change in the voltage difference of the subscriber line is detected, the selector is selected. And a local device having a second connecting means for disconnecting an output from the circuit from the subscriber line.