Patent GB-229371-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone systems
IPC: H04Q3/42
Filed: 1923-11-14
Abstract: 229,371. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. Nov. 14, 1923. Order apparatus.-In a telephone system in which subscribers' numbers are transmitted from an automatic to a manual exchange in code combinations of light positive, light negative and heavy negative impulses in accordance with the tables shown in Fig. 6, the coded digits are decoded by the relays shown at the top of Fig. 3 and stored on relay register sets D2, after which they are transferred to a second group of relay sets D3 to control a lamp indicator L. When a given call is connected to the decoder, relay 500 energizes and relays 501, 502, 503 are connected in series with the two conductors of the interexchange trunk over which the coded impulses are transmitted. Decoding of impulses and setting of register relays D2. The relays 501, 502, 503 respond respectively to positive impulses, strong negative impulses and all negative impulses. From a consideration of Fig. 6 it will be seen that each digit contains two negative impulses which may or may not have a positive impulse preceding or. following the first negative impulse. A positive impulse preceding the first negative impulse operates the first register relay of a group over contacts 506, 507, 514. The first negative impulse of a digit partially operates relay 509 and at the end of the impulse this relay completely operates so that a positive impulse following the first negative impulse will operate the third register relay. The second negative impulse if a digit partially operates relays 508, 517 and at the end of the impulse which is also the end of the digit, both these relays fully operate, the former releasing relay 509 and then itself, the latter transferring the control leads to the register relays of the next digit. If either or both of the negative impulses are strong, either or both of the second and fourth storage relays are operated. Thus, the decoding of a first digit 4, for example will operate relay 524, whilst a final digit 7 will cause the operation of relays 530, 533. Transfer of wanted number from register relays D2 to indicator relays D3. At the end of the last digit, the complete operation of relay 531 releases relay 542 so that lead 552 is now grounded over contacts 549, 537, 547, 544 and the indicator relays 528 &c. corresponding to the operated register relays 524 &c. are energized. Relay 539 is also enegrized to operate relay 540 and to complete at armature 545 the lighting circuit for the selected lamps L. Release of decoder. The grounding of lead 552 also causes the release of relay 500 and the unlocking of all the operated relays D2 so that a second wanted number may now be set up on these relays. When the first connection has been completed by the operator, relay 539 releases and the opening of contact 545 extinguishes the lamps whilst the momentary operation of relay 541 unlocks the indicator relays 528 &c. If a second number is waiting on the register relays D2, it will be transferred to the indicator as soon as the release of relay 540 grounds the lead 552.