Patent GB-519733-A (GB)
Title: Improvements in or relating to impulse senders for use in telephone or like systems
IPC: H04Q1/34
Filed: 1938-09-28
Abstract: 519,733. Automatic exchange systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., WOODLAND, C. R., McCLEW, J. W., and HOUGHTON, E. 1. Sept. 28, 1938, No. 28248. [Class 40 (iv)] A keyboard-controlled register-sender incorporates a mechanical impulse regenerator of the kind described in Specification 458,095. The pawl 25 which drives the receiving ratchetwheel 26 is carried by the stepped armature 21 of a receiving magnet 22, and the movement of this armature is limited by one of a series of stops brought into its path by one of the magnets 12-20 corresponding to the digits 1-9 or by a fixed stop corresponding to the digit 0. The return movement of the armature therefore rotates the wheel 26 through an appropriate angle. The mechanical construction is similar to that described in the prior Specification, except that the sending wheel is driven through gearing by a spring which is arranged to be rewound by a self-interrupting magnet 62 or motor while sending is taking place. First arrangement, Fig. 5, in which sending starts as soon as first digit is registered. Upon depression of a digit key, relay MK energizes in series with one of digit magnets DM 1-9 or with an equivalent resistance and connects up the receiving and marking magnets RM, MM. Upon release, the former rotates the receiving wheel R as described above, and the latter pushes an appropriate pin through the plate P into the path of a resetting member on the sending wheel S. Relay ON energizes over off normal contact N and makes a circuit for relay P over the resetting member and the displaced pin which it engages, whereupon the sending magnet TM operates momentarily to reset the pin and release the wheel S for the transmission of the first digit. Two slow-release relays IP, IPR provide the interdigital pause between the operation of P over the displaced pin at the end of a digit and that of the sending magnet TM. When all the digits have been sent, ON is disconnected at contact N. The operation of relay CKR over the cancel key CK disconnects IP, IPR so that the digits already keyed are discharged quickly. Second arrangement, Figs. 6, 7, in which the sender is controlled from a distant A operator's keyboard, and sending does not start until all the digits are registered. Upon seizure of the sender by a hunting switch associated with an incoming junction, relay BG operates and a switch PH takes into use an idle voice-frequency relay set, relays K, KA being energized, and the keyed digits which are received as single or mixed frequencies operate one or more of relays W-Z in series with DS. These relays effect the operation of relay MK in series with one of the digit magnets DM 1-9 or with an equivalent resistance, as in the first arrangement above. A sequence switch SR which controls cam contacts SRN, A, B is advanced one step as each digit is registered, and in position 5, assuming that four digits are keyed, contacts A operate, releasing the voice-frequency relay set and connecting up ON. The start wire ST leading to the junction relay set is earthed, the impulse springs IMP are bridged across the loop, and the stored digits are sent as described above. On the relapse of ON, the sequence switch SR advances to position 1, the sender being marked busy by the opening of contacts B until this position is reached. Relay CK, which is controlled by the operator's cancel key, by earthing wire P causes a fresh sender to be associated with the junction. The sequence switch advances to position 5, and the stored digits are discharged quickly as in the first arrangement above. In a modification of the above arrangement, in which the sender is controlled from a B operator's keyboard associated over the switch PH, relay CK when connected up by the cancel key maintains the same sender in use.