Patent GB-811561-A (GB)
Title: Improvements in or relating to dictation system
IPC: H04M1/65
Filed: 1955-09-06
Abstract: 811,561. Dictation systems. DICTAPHONE CORPORATION. Sept. 6, 1955 [Sept. 20, 1954], No. 25514/55. Class 40 (4). In a remotely operated dictation system in which one of a plurality of dictator's stations is arranged to be connected over a group of three lines to central recording and control apparatus, control functions are established by relays which respond selectively to a variety of current combinations in the lines which are set up by a pair of manually operable switches at each instrument, one controlling the current flow through two of the lines such that any one of three current conditions may be established therein, and the other controlling the flow through another pair including the third line so that either of two current conditions may be established therein. Recording.-Operation of the cradle switch 24 of a dictator's instrument 10, Fig. 1A, connects a resistance 52 across lines 12 and 14 and the resulting current through windings of line relay 84 which is insufficient to operate the relay raises the potential of line 12 to increase the current through a valve 106 and thus operates a record relay 108. Resistance 52 is shortcircuited and the line relay 84, which is operated from source 92, energizes " in-use " relays 134, 136 releasing relay 108. Relay 84 is held despite the reinsertion of the resistance. A hold relay 164 operated by relay 136 applies power to lines 16, 18 which lights busy lamps 188 at all stations, energizes self-locking, privacy or lockout relays 32 at other than the dictator's station and connects power to driving motor 260 and the power pack 262 of amplifier 72. Ripple from the source also produces a hum in the receivers 20. The hold relay 164 releases also a slow-to-release tone relay 216 and during the period when both are operated a 1200 c/s. generator 230 also energized by the operation of relay 136 is connected to lines 12, 14 to indicate to the dictator that he has control. When the dictator operates " record " switch 300, relay 108 reoperates and actuates a clutch relay 304 to energize clutch solenoid 264. The latter also opens a short-circuiting switch 346 across the recording head 322. Recording is effected over lines 12, 14, transformer 58 and record-reproduce switch 70. Playback.-In order to listen to a portion of the recorded material the dictator throws a key 350. Resistance 52 is short-circuited and the clutch solenoid is energized as before. Lines 14 and 16 are commoned and control relay 362 is energized thereover to energize playback solenoid 394 through contacts of function relay 382. The solenoid 394 moves switch 70 to " reproduce " and the signal picked up from reproducer 74 is amplified and fed over lines 12, 14 to receiver 20. Relay 382 is made to release before relay 304 when the playback key is released so that the connection is maintained. Correctionmark.-To make a correction mark on a pad provided at the machine, the dictator throws switch 404 and the function relay 382 is energized as in " playback," but resistance 52 is disconnected from the line so that the tape cannot be driven. Marking solenoid 612 is energized over relay 414 which operates over relays 382, energized and 318, released. The solenoid 612 incorporates a motion limiting latch which is withdrawn by the action of relay 414 to permit a longer mark being made on the pad, the shorter mark being reserved to indicate the end of a recording. Signalling attendant.-The attendant call switch 40, when thrown, opens the connection between lines 12, 14 and connects lines 14, 16. Relays 84, 134, 136 and 164 are released but the last-mentioned which is slow-to-release is reenergized by the actuation of control relay 362. Function relay 382 which is also energized by the control relaycompletes a circuit for an audible calling device and when the attendant's relay 314 is actuated in response to the attendant lifting his handset, the circuit is opened, and power is supplied to the microphone 460. The dictator may if the power is inadequate operate " record " switch 300 to short out resistance 52 and in such a circumstance the attendant may break the clutch circuit thus energized by opening switch 492. Alternatively the clutch may be actuated and the conversation recorded. Miscellaneousfeatures.-A switch 502, which is operated by the machine carriage when only 2 ¢ minutes of recording medium remains available, allows recording to continue but prevents any further calls by the de-energization of a normally operated limit relay 338 when the hold relay 164 is released at the end of a call. De-energization of the limit relay renders the machine inoperative by breaking the clutch power circuit, notifies the attendant by entergizing the oscillator 230 and applying it to loud-speaker 546, and notifies all stations by maintaining lamps 188 busy. A neon light 510 on the machine isalso made to flash. Limit relay 338 is also de-energized if limit switch 520, both lever switches 522, 524 or the contacts of tube relay 530 are opened. The lever switches are opened during changing of the medium and the tube relay is energized by the amplifier anode current. Since anode current is not supplied during inactivity an alternative path is provided by the de-energized hold relay. Warning switch 576 is closed by the carriage when only 30-60 seconds of medium remains and a pulse generator 578 is energized. As a result pulses of tone from oscillator 230 are applied to the dictator's receiver 20 over lines 12, 14 by pulse relay 66. The recording head is shorted during pulsing to prevent the pulses being recorded. The shorter, end-of-letter mark can be made on the indicator pad by the dictator hanging up his handset or manually operating the cradle switch. Condenser 604 discharges through the solenoid 612 when relay 164 is released. The privacy relays 32 may be made as a plug-in unit, and may be dispensed with, wired dummy plugs being alternatively provided. Specifications 698,444 and 742,490 are referred to.