Patent GB-805599-A (GB)
Title: Key senders
Filed: 1956-06-11
Abstract: 805,599. Automatic - exchange systems. AUTOMATIC ELECTRIC LABORATORIES Inc. June 11, 1956 [July 13, 1955], No. 17975/56. Class 40 (4). Digits can be entered in code on a magnetic wheel under the control of a keysender or a dialling device and then transmitted to line automatically at correct dialling speed. The magnetic wheel comprises four discs 100W, 200X, 300Y, 400Z rigidly mounted on a common shaft and each having a number of magnetizable spokes 120. Operation of one of digit keys K1-K9, K0 discharges a condenser C10 through one or two of four coils 206-209 according to a code to magnetize the associated radial spokes 120. The operated digit key also energizes motor magnet M160, release of the key restoring the magnet so that the discs 100W-400Z are advanced one step. Subsequent digits are registered in like manner. When registration is complete, start key KS is operated to energize motor magnet M160 which self-interrupts as long as the start key is held down until the set of radial spokes 120 bearing the first digit appears under the detection armatures 110-410 to close one or two of the contacts 100-400. The operated contacts energize start relay R400 which releases motor magnet M160 to stop rotation of the discs. R400 also operates R100 to prevent further registration of digits due to accidental operation of digit keys. The operated contacts 100-400 apply ground to appropriate contacts of the upper and lower levels of retranslate switch S170 while R100 energizes pulse-out relay R110. A source 180 of pulses energizes and restores pulse-in relay R120 at dialling speed, the resulting operation of contacts 121 becoming effective for pulsing line conductors 146, 147 at the energization of pulse-out relay R110, just mentioned. Motor magnet M150 follows R120 in anti-phase to advance re-translate switch S170 step by step in time with the outgoing impulses until wipers 171, 172, simultaneously encounter ground from the contacts 100-400. Relays R200 and R300 then pull up to energize R800 which operates impulse arresting relay R900 and releases R110 slowly. R900 closes the pulsing- out loop at 901 to stop further impulsing to line. R900 also energizes an erase relay R500 which applies reverse current through the coils 206-209 to erase the information relating to the digit which has been sent to line. M160 operates and restores to advance the magnetic wheel one step and M150 drives re-translate switch S170 no home position where R200, R300, R800 and R900 restore. This takes place during an interval equal to an interdigital pause. Subsequent digits are sent in like manner. If the start key KS is not operated within a predetermined time after the registration of the last digit transmission is effected automatically by operation of automatic start relay R600. If an error is made in keying a correct key KC may be operated to erase the existing registrations. The keysender may be replaced by a conventional dial, the dialled digits being translated into coded magnetizations in the manner described in Specification 771,464. The contacts of the keysender may be replaced by rectifiers (Fig. 6, not shown).