Patent GB-421059-A (GB)
Title: Improvements in devices for recording and reproducing telephonic messages
IPC: H04M1/65
Filed: 1933-06-10
Abstract: 421,059. Substation equipment. RICCHIARDI, P. C., 10, Rue Faraday, Paris. June 10, 1933, No. 16651. Convention date, June 11, 1932. [Class 40 (iv)] [See also Group XXXVIII] A privileged calling subscriber on receiving a phonographic message that the wanted subscriber is absent transmits a code number in the form of voice frequency current impulses and then receives a further phonographic message intended for himself alone. Means are provided also at the called station for recording a message from the calling subscriber whether privileged or non-privileged. The amplifiers used in recording and reproducing may be used when the subscriber is present to provide a loud-speaking telephone system, and the recording and reproducing arrangements, which in the system described are of telegraphone type, may be used as a dictating machine. Transmission of general reply message and reception of message from non-privileged subscriber. The bell 8 completes a circuit for a magnet 11 which unlatches the switch hook. This, in addition to its normal function of cutting off the bell and extending the incoming line to the telephone circuits over wires 36, 37, at springs s, c, makes a momentary circuit at springs 19, 20 for a sluggish relay 25, which connects positive battery to a number of points marked + on the drawing and a circuit for the driving motor 35. On the operation of 25, 101 withdraws a detent to enable the spool 91A carrying the general reply wire to be driven and energizes 92 which connects the telegraphone magnets 88, 89 to the input circuit of a class B amplifier V2 the output of which is connected to the line. The anode feed circuit of this amplifier and of the amplifier V1 include the relay 25 which is therefore held while telephonic currents in either direction are being amplified but falls back when such currents cease for a predetermined time. At the end of the message a contact bar 114A changes over, releasing 101, 92 and energizing 127 which withdraws a detent from a spool 85A driving a blank wire. Since, owing to the relapse of 92, the telegraphone magnets are now connected to the output circuit of amplifier V1 the input circuit of which is connected to the line, the incoming message is recorded. On the cessation of speech, 25 falls and restores normal conditions, the switch hook being reset by a magnet 142 and the contact bar 114A by magnets 638, 635. Transmission of individual message to and reception of message from privileged subscriber. On receiving the general reply message and before relay 25 can fall back, a privileged subscriber dials a multi-digit number characteristic of himself. The dial, which is preferably a separate one C2, at each movement off normal gives an impulse to a magnet 220 with a reed armature tuned to a frequency f1 and during its return delivers a number of impulses to a magnet 222 with an armature tuned to frequency f2. These armatures with the aid of field coils 301, 303 produce currents of corresponding frequency in the input circuit of a valve V3 the output circuit of which is connected to the line. The output circuit of the receiving amplifier V1 at the distant station includes relays 70, 68 mechanically tuned to these two frequencies and controlling respectively a distributer 407 and a number of digit registers 144A .. 144E. Each wiper of these registers (except the first) is connected by a plug to one of the terminals in the corresponding level of the preceding register. Consequently if one of the pre-determined codes is dialled a circuit is made over one of the leads 620 .. 524 for one of the controlling magnets 610A .. 610E of spools bearing individual messages. The selected magnet energizes 92 to switch the telegraphone into the transmitting condition. The distributer on moving off normal makes a temporary circuit for magnet 635 which restores the bar 114A sufficiently to open the contacts 623, 125 but not to close the contact 104. As a result, 127 is released to stop the spools 85A, 85B carrying the blank wire. At the conclusion of the individual message however 114 B changes over and 127 is re-operated. Any message from the subscriber is then recorded and the apparatus is released as previously described. Loud - speaking telephone system. With switches 38, 39, 52, 53 and 58, 59 in their upper position, loud-speaker 72 and microphone 73 are associated with the receiving and transmitting amplifiers respectively, the telegraphone being disconnected. Recording and reproducing locally. Circuits can be made by means of switches and of plugs (not shown) associated with the switch contacts whereby the telegraphone messages may be reproduced by the loud-speaker 72 or whereby the microphone 73 may be associated with the telegraphone for local recording. Battery 40 is connected up when it is desired to erase the messages.