Abstract:
In a cordless telephone, normal tape recorder or micro cassette tape recorder is operated by memberance touch and is coupled to the main body of the telephone. The tape recorder operates on a cordless remote-control unit at remote distances from basic unit by means of control switch (record, play basic, rewind, fast forward, stop) attached to the remote unit. This arrangement provides a remote control record/play back cordless telephone to record and play back the speech content in the remote unit while the opposite party is on the telephone or before the speaking begins. The remote unit includes a digital encode circuit that converts the signal of a selected function for control switch into a digital signal corresponding to the selected function, FM-modulates and amplifies said digital signal, and then cordlessly transmits it to base unit. On the other hand, base unit includes a complementary digital decode circuit and transceiver.

Description:
BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a circuit diagram of a telecontrol unit in a transmitter-receiver of a radiotelephone according to present invention. 
     FIG. 2 is a circuit diagram of a telecontrol unit in the main body of the radiotelephone according to the invention. 
     Reference characters in the drawings indicate parts or units as follow. IC 1 , IC 2 , IC 3 , IC 4 , IC 8 , IC 9 , IC 10 , IC 11  indicate tone decoders; IC 5  and IC 12  decoders; IC 6  an encoder; 9, 10, 11, 27, 28, 29 tone oscillators; S 3 , S 4 , S 5 , S 6 , S 7 , S 8  control switches for the recorder; LED 1 , LED 2 , LED 3 , LED 4 , LED 5 , LED 6  light emitting diodes: 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Present invention is related to a telecontrol system by means of which a recorder attached to a main body of a radiotelephone is remote controlled from a transmitter-receiver. 
     In prior arts, there have been some systems in that a recorder is attached to a telephone to record some of conversation in telephone communications. However, in a radiotelephone of which receiver is separated far from the main body of the telephone, the system has a drawback of inconvenience that a user has to come up to the main body to operate the recorder whenever a need for recording arises. 
     Present invention is directed to eliminate such a drawback in the conventional systems and to provide a system in that the recorder is remote controlled from the transmitter-receiver by telecontrol units provided on both the main body and transmitter-receiver of a radiotelephone. 
     Referring to the attached drawings, the present invention is described in detail as follows. 
     On the part of the transmitter-receiver, the system is so arranged as in the FIG. 1 that output of an FM detector is connected in parallel to input terminals (IN) of tone decoders (IC 1 , IC 2 , IC 3 , IC 4 ), output terminals (OUT) of the tone decoders (IC 1 , IC 2 , IC 3 ) being connected through a decoder (IC 5 ) to light emitting diodes (LED 1 , LED 2 , LED 3 , LED 4 , LED 5 , LED 6 ), the output terminal (OUT) of the tone decoder (IC 4 ) and a stand-by switch (S 2 ) respectively connected to inputs of a NOR gate (G 1 ), output of the gate and an output terminal (MUTE) of a dialer (13) respectively to inputs of an OR gate (G 2 ) for further connection to a muting circuit (7), recorder control switches (S 3 , S 4 , S 5 , S 6 , S 7 , S 8 ) through an encoder (IC 6 ) to inputs of tone oscillators (9, 10, 11), input of a tone oscillator (12) to output (OPL) of the dialer (13), and outputs of the tone oscillators (9, 10, 11, 12) together with output of a voice amplifier (15) to input of an adding unit (IC 7 ). 
     On the part of the main body as in the FIG. 2, output of an FM detector (22) is connected in parallel to input terminals (IN) of tone decoders (IC 8 , IC 9 , IC 10 , IC 11 ), output terminals (OUT) of the decoders (IC 8 , IC 9 , IC 10 ) connected through a decoder (IC 12 ) to a common electronic audio recorder (26) and also directly to inputs of tone oscillators (27, 28, 29), and outputs of the oscillators (27, 28, 29), together with output of a tone oscillator (30) connected to a photo coupler (31) and with output of a buffer amplifier (32), to input of an adding unit (IC 13 ). 
     The system is such that oscillation frequencies of the tone oscillators (9, 10, 11, 12 and 27, 28, 29, 30) on both parts stated above are different from each other but are arranged to correspond to locked frequencies of their responsive tone decoders (IC 8 , IC 9 , IC 10 , IC 11  and IC 1 , IC 2 , IC 3 , IC 4 ). 
     Unexplained characters in the drawings indicate the following units; That is, 1 and 18 indicate high frequency amplifiers; 2 and 19 mixers; 3 and 20 local oscillators; 4 and 21 intermediate amplifiers; 6 and 24 buffer amplifiers; 8 a voice amplifier; 14 a key board; 16 an 33 FM modulators; 17 and 34 high frequency power amplifiers; 23 a tone trap; 25 hybrid transformer; G 3 , G 6 , G 9 , G 12 , G 15 , G 18 , G 21 , G 24  NAND gates; G 4 , G 5 , G 7 , G 8 , G 10 , G 11 , G 13 , G 14 , G 16 , G 17 , G 19 , G 20 , G 22 , G 23 , G 25 , G 26 , G 27  inverters; S 1  a source switch; R 1  thru R 49  resistances; C 1  thru C 16  capacitors; ANT 1  thru ANT 4  antennas; Ry a relay; Q1 a transistor; TEL LINE telephone circuit line; SP a speaker; MIC a microphone; A a receiver part; B a transmitter part. 
     The manner of operation of the invention will be explained in detail with reference to the drawings. 
     The transmitter part (B) of the transmitter-receiver is connected to a source for power supply only while the stand-by switch (S 3 ) is on ON-position and then activates for operation. On pushing one of the recorder control switches (S 3 , S 4 , S 5 , S 6 , S 7 , S 8 ) one of input terminals (D 1  thru D 6 ) of the encoder (IC 6 ) obtains a high level and output terminals (Q 1 , Q 2 , Q 3 ) give out a responsive signal of binary digit. For example, on pushing the switch (5) the encoder outputs a signal of a binary digit &#34;101&#34; responsive to a decimal digit &#34;5&#34;. 
     Succeedingly, a tone oscillator (9, 10 or 11) connected to the output terminal (Q 1 , Q 2  or Q 3 ) in high level (H) of the encoder (IC 6 ) is activated to oscillate, but the oscillator connected to the output terminal in low level (L) is not activated for oscillation, so that binary digital data in a multi-frequency system be produced for addition at the adding unit (IC 7 ) and then modulated by an FM modulator (16) for transmission. 
     The signal, being received at the main body of the radio telephone, is carried through an FM detector (22) for detection. Since locked frequencies of the tone decoders (IC 8 , IC 9  and IC 10 ) connected to the output of the detector (22) correspond respectively to the responsive oscillation frequencies of the tone oscillators (9, 10 and 11) on the part of the transmitter-receiver, only the output of a tone decoder (IC 8 , IC 9  or IC 10 ) responsive to the tone oscillator in operation gains high level (H), while the others remain in low level (L). Consequently, a signal of binary digit corresponding to the output of the encoder (IC 6 ) enters the input terminal (D 1 , D 2 , D 3 ) of the decoder (IC 12 ) for a responsive output terminal (Q 5  in the above stated example) of the decoder (IC 12 ) to gain high level (H) so that the recorder (26) be activated for operation synchronously with the pushing of control switch at the transmitter-receiver. 
     Outputs of the tone decoders (IC 8 , IC 9  an IC 10 ) are also connected to the tone oscillators (27, 28 and 29) so that only the tone oscillator being connected to the output in high level of the decoder may produce oscillation. Consequently, the signal is produced as data of binary digit in a multifrequency system to be added at the adding unit (IC 13 ) and then to be modulated through the FM modulator (33) for transmission, which is received at the transmitter-receiver and carried through the detector (22) to enter the tone decoders (IC 1 , IC 2  and IC 3 ). Succeedingly, the output of the tone decoder (IC 1 , IC 2  or IC 3 ) is given out in a binary digit corresponding to the output of the tone decoder (IC 8 , IC 9  or IC 10 ) and then converted into a decimal digit through the decoder (IC 5 ) to light up a responsive light emitting diode (LED 1 , LED 2 , LED 3 , LED 4 , LED 5 , LED 6 ), thereby enabling to confirm the reliable transmission of control signal from the transmitter-receiver to the body of telephone. 
     On calling from the transmitter-receiver, the tone oscillator (12) and the tone decoder (IC 11 ) are activated by the output (OPL) of the dialer (13) to put the relay (Ry) on ON-position so that a hybrid transformer (23) and the telephone line make an intermittent connection between them. 
     On a telephone call from the outside while the stand-by switch (S 2 ) is OFF to cut off the source for the transmitter part (B), the photo coupler (31) of the main body picks up the signal to activate the tone oscillator (30) for transmission, which is received by the receiver to make the output of the decoder (IC 4 ) gain high level (H) so that the muting circuit (7) in a cut-off state of stand-by is put on through. The signal of the tone oscillator (30) carried through the FM detector (5) is given out through the voice amplifier (8) to the speaker (SP) to inform the call to a user. 
     As stated above, the present invention provides a telecontrol system for a recorder attached to a radiotelephone, in particular, by means of which the recording of telephone conversation between users may be controlled at the receiver far apart from the main body, and in which the transmission of control signal to the recorder may also be confirmed for its reliability at the transmitter.