JPS6273665U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the internal configuration of a telephone in an embodiment of the recording operation circuit of the present invention, and FIG. 2 is a block diagram of the overall construction of an embodiment of the recording operation circuit of the present invention. Explanation of main figure numbers: 1 ...First telephone, 2 ...Second telephone, 4 ...Signal transmitting circuit, 5 ...Signal receiving circuit, 17...Second impedance circuit, 18 ...
...Voltage detection circuit, 19... Signal identification circuit, 20...
...Latch circuit.

Claims (1)

[Scope of utility model registration request] In a first telephone set and a second telephone set connected in parallel to the same line, the first telephone set includes a recording switch for recording at least the contents of a call made by the first telephone set, and a recording switch activated by the recording switch and transmitting a coded pulse signal. A signal generation circuit to output,
a DC impedance circuit that changes the telephone line voltage in response to the output of the signal generating circuit; A signal identification circuit that outputs a drive signal when the detection signal of the detection circuit matches a set coded pulse signal; a latch circuit that is activated by the drive signal of the signal identification circuit and outputs a constant signal; and a recording means for performing a recording operation based on the output, so that when recording the contents of a call on the first telephone, by operating the recording switch on the first telephone, the desired recording means on the second telephone is activated, and the desired recording means on the second telephone is activated. A communal telephone recording operation circuit characterized by being capable of recording the contents of a telephone call.