Patent GB-853990-A (GB)
Title: Improvements in or relating to the control of dictating machines
Inventor: GRAY CHARLES LANCE
IPC: H04M11/10
Filed: 1958-05-21
Abstract: 853,990. Centralized dictation systems. AUTOMATIC TELEPHONES & ELECTRIC CO. Ltd. May 21, 1959 [May 21, 1958], No. 16340/58. Class 40 (4). In a telephone exchange system provided with a dictation-recording machine accessible to one or more subscribers' stations on the exchange, a subscriber's station to be afforded the dictation-recording facility is provided with a single pushbutton switch or the like for the control of the machine, the switch being arranged when operated to connect a source of potential to the subscriber's line and, when a connection has been established between the subscriber and the machine, switching equipment associated with the machine is adapted to respond to different manipulations of the switch in predetermined sequences to enable the necessary controls to be exerted on the machine. As shown, a relay set associated with a dictation-recording machine is arranged for use with different types of P.B.X. by means of straps. With a P.M.B.X., strap SA is inserted and terminals 1B, 1D, 2D, and 1E or IF are used. With a P.A.B.X. having battery-testing selectors, terminals 1B, 1C, 2C, and 3C are used, 1B being replaced by 1A if the selectors are earth-testing. Seizure of recording machine and recording of dictation.-Relay A (but not differential relay D) operates in the calling loop on leads 23, 24 and brings up relay B. This lights a busy lamp at the supervisor's position, starts valve VA oscillating at 400 c/s so that the calling subscriber hears a tone signifying that the machine is in the " stop " condition, and energizes relay DD. In the case of a P.M.B.X., with strap SA inserted, relay BR also operates. The calling subscriber now momentarily operates his push-button which connects earth to the calling loop. Differential relay D operates, followed by relays DA and BR (if not already operated). The " stop " tone ceases. Relay DD holds, having a release period of 2-3 seconds. On the release of the push-button, relay D falls back, energizing relay DB which connects earth to " on " lead 20 to start the machine. The calling subscriber may now record his dictation via speech wires 23, 24 and transformer T1. To stop the machine, a further brief operation of the push-button reenergizes relay D which releases relay DA so that valve VA resumes the " stop " tone, and the relapse of relays D and DB on the release of the push-button stops the machine by transferring the earth connection from " on " lead 20 to " off" lead 19. Playback.-For this the machine must be in the " start " condition with relays DA and DB energized. The subscriber depresses his push-button and holds it operated, so that the operation of relay D releases both relays DA and, after a delay, DD. Relay DA re-operates, bringing up relay H. This changes the frequency of oscillator VA to 1000 c/s, earths terminal 17 to energize the playback relay of the machine, switches transformer T1 from the input to the output of the machine, and energizes relay P which starts VA oscillating and earths the "backspace" " terminal 21. The circuit of relay P is self-interrupting, so that the subscriber hears an intermittent tone while the machine backspaces in steps. When the subscriber releases the push-button, relay D falls back and relay DD is re-energized, releasing relay P to stop the tone and the backspacing. The subscriber now hears the playback of the recording via transformer T1. He may stop the playback by a brief operation of the push-button, bringing up relay D to release relay DA. On the release of the push-button, relay D falls back, followed by relays DB and H so that the machine is in the " stop " condition. The subscriber hears 400 c/s tone, and he may resume dictation by momentarily operating the push-button as before. Warning that recording medium (e.g. tape) is nearly exhausted.-A signal on terminal 22 consisting of a continuous or intermittent earth causes valve VB to generate a characteristic tone which is heard by the calling subscriber. Call to supervisor.-The machine must be in the " stop " condition with relays DA and DB released and DD energized. If the calling subscriber holds his push-button operated, relays D and DA are operated, stopping the tone from oscillator VA, and relay DD falls back after a delay, ringing the bell at the supervisor's position (so that -the calling subscriber hears a ringing signal by induction over relay A) and energizing relay DC. This completes a self-interrupting circuit for relay P which now has a longer release time since condenser C1 is in its circuit, relay H not being operated. Relay P flashes a calling lamp at the supervisor's position and causes oscillator VA to send intermittent 400 c/s tone to the calling subscriber. If the subscriber releases his pushbutton, the relapse of relay D re-operates relay DD to disconnect the bell, but relay DC remains energized and relay P continues to flash the calling lamp. The subscriber may ring the bell again by once more holding the pushbutton operated, bringing up relay D to release relay DA followed slowly by relay DD which re-operates relay DA to ring the bell. The supervisor answers by operating an answer key KA at the position at which the call lamp is flashing. This completes a speech circuit and also releases relays DC, DA and BR (except in the case of a P.M.B.X., in which relay BR is held by strap SA), thereby disconnecting the bell and the calling lamp. At the end of the conversation, the supervisor restores key KA and the equipment reverts to its normal " stop " condition, the subscriber being able to control the machine by means of his pushbutton as before. If the supervisor does not answer a call, or has been called in error, the subscriber briefly operates his push-button, the operation of relay D then releasing relay DA. On the release of the button, relays D and DC fall back. The bell and calling lamp are thus disconnected and the machine is in the " stop " condition. Release and testing.-When the calling subscriber hangs up, relay A falls back, followed by relays B and DD and any other operated relays, except relay BR which is held by key contacts KA3 so that the equipment remains busied and the calling lamp glows steadily. The supervisor may release the equipment by briefly operating the answer key KA to release relay BR or may test the recording machine by operating first the test key KT and then the answer key KA. This places the supervisor in the position of a calling subscriber.