Patent GB-307368-A (GB)
Title: Improvements in automatic or semi-automatic telephone systems
IPC: H04M3/60
Filed: 1927-11-02
Abstract: 307,368. Standard Telephones & Cables, Ltd., (Deakin, G.; and Polinkowsky, L.). Nov. 2, 1927. Automatic and semi-automactic exchange systems.-A call from an automatic to a manual exchange is set up over an operator's position associated with the automatic exchange and provided with call indicating arrangements, the number of the wanted subscriber and the automatically selected junction being notified to the manual operator over an order wire. The position may be arranged anywhere in the junction, but is preferably at the automatic exchange. The junction seized over a group selector, is automatically connected over the operator's position shown in Figs. 1 and 2 and finder switches to an idle call indicator equipment, Figs. 3 and 4, comprising register switches R10, Ru and storage relays, controlled by sequence switch R, Fig. 3. Figs. 1 and 2 should be placed above Figs. 3 and 4. Discriminating means is employed to determine whether a four or five digit number is to be registered, the first two or three digits being registered and stored, after which the registers R10, Ru pass to a normal position and then register the remaining two digits. The invention is described wth reference to automate systems such as are described in Specifications 261,109 and 307,369 in which the switches at a calling exchange are controlled by a signal comprising a temporary bridge across the speaking wires at the called exchange in addition to the usual answering signal. As in the present case the called exchange is a manual one, so that the temporary bridge is not given, the sequence switch R is arranged to give this signal. The operator may, if the number is incompletely dialled or not properly shown, put herself into communication with the calling subscriber and she may, semi-automatically, temporarily bridge the junction if the switch R has not done so. The junction is held engaged until the subscriber hangs up. Seizure of call-indicator equipment and registration of wanted number. When operator takes up her duties, relay Txr, Fig. 2, energizes over her transmitter and completes the circuit of Por which in turn closes the units Csr, Cs1r. Ground on the c wire incoming from the previous selector is now extended over contacts of Abr and Cs1r to relay CR which completes the circuit of Dmr and Fsr. Relay Str, Fig. 3, pulls up over contacts of Fsr and closes the circuits of the magnets PF of the finders of idle registers. When the calling junction is found, relay Gtr energizes over cam F of the sequence switch R and terminal g, opens the circuit of PF, and closes, a circuit for Shr which completes the circuit of Prr over cams D, J. Sequence switch R now moves to position 2 in which relay Glr energizes over contacts of Fcr, cam K, Prr, b wire, fundamental circuit at the calling register, a wire, cams T and R. Relay Pcr energizes over cam L and cam R, Fig. 4, and locks over V, R to complete the fundamental circuit, which is similar to that just traced except that it goes from Glr over Y, contacts of Glr and front contacts of Pcr. Relay Pcr closes the circuit of register magnet R10 (cam N, right front Pcr, cam L right front Glr, cam R) to set the register in accordance with the first digit, the calling register being counted out by impulses sent back by interrupter of R10 over cam H of R and the fundamental. Relay Glr falls back when the fundamental is opened. The register switches, R10, Ru are arranged to receive four or five digits according as to whether the first digit is even or odd. The first, second and fourth digits of a five digit number are registered by R10 while Ru registers the third and fifth, R10, Ru being used alternately for a four digit number. The release of Glr drives switch R to position 7¢, Per being released when the switch leaves position 2. In position 2¥, a check is made to determine whether the first digit is even or odd. If the digit is even, one or a combination of relays Dar, Dbr, Dcr become energized over cams D, E, F of R10 and cam R of switch R. These relays lock up over cams Q, R and store the digit. In passing position 3¢, R10 energizes over cams B of R10, M of R, contacts of Dar or Dbr, cams P, R and moves to a sub-normal position S (between 10 and 11). When sequence switch R reaches position 7¢, its circuit is again closed over cams B of R10 and S of R and the switch moves to position 8¢. Relay Glr again energizes over the fundamental followed by Per (over cam L, contacts of Glr, cam M, contacts of Dar or Dbr and cams P, R) which locks over cams V, R as before. The second digit is registered by R10 as before, Glr releases, and sequence switch R moves to position 10, Per being released in position 81. This digit is always odd. In passing position 9“, one or a combination of relays Mar, Mbr, Mcr become energized over cams D, E, F of R10 and lock up over cam Q to store the digit. In position 10, R10 is returned to normal over cams B of R10 and M of R, relays Glr and Per energize as before, and the circuit of register switch Ru is completed over cams N, L, R of switch R to register the hundreds digit. Relay Glr falls back and completes a circuit for switch R which moves to position 11¢. Relay Per releases on leaving position 10, and at position 10¥, one or a combination of relay Car, Cbr, Ccr become energized over cams C, D, F of Ru and lock up over Q, R to store the digit. At the same time, relay Mpr or Mir is energized over cam E of Ru according as to whether this digit is odd or even. On reaching position 11¢, Ru energizes over cams B of Ru and V of R and moves to a sub-normal position S while relays Glr, Per energize as before and complete the circuit of register switch R10. The tens digit is now registered by R10 in the same manner as the first two digits but the digit is not stored, and RIO remains in the set position and closes one of the contacts of its cams I, G, H. Relay Glr releases to move sequence switch R into position 12¢ and Pcr relapses on passing position 11¢. In position 12¢, Glr and Per re-energize and register Ru is set in accordance with the units digit and closes one of the contacts of its cams M. N, L. Ru remains in this position and the digit is not stored. Priority and free indicator test; display of number. When Glr releases on opening of the fundamental, sequence switch R moves to position 13¢ where a test is made to ascertain whether another register equipment is awaiting the release of the call indicator. In this position, Gtr enerizes over cam F and, if no other register is in position 13¢, relay Shr pulls up and completes a circuit for Glr over cams X, K and contacts of Per which relapsed on leaving position 12¢. Relay Shr, being marginal and in parallel with similar relays of other registers, does not pull up if another register is standing in position 13¢, and in this case, the present register waits until the other register moves out of position 13¢. Relay Glr, on pulling up, moves sequence switch R to position 14¢, relays Gtr, Shr and Glr releasing on leaving position 13¢. In position 14¢ Gtr again energizes and Shr tests to ascertain if the call indicator is busy. If no other register is standing in position 14¢ to 17, Shr pulls up, followed by Glr, and the switch R moves to position 17 in which relays Alr, Vlr pull up over cam E, contacts of Prr and of Elr, Fig. 2. Relay Alr completes, over contacts of the Storage relays and cams I, G, H, M, N, L of registers R10, Ru, the circuits leading from the bottom of Fig. 4 to the lamps of the call-indicator. At position 16, relay Abr, Fig. 1, pulls up over terminal d, cam G and front contacts of Bcr which become energized in position 13“. Relay Abr. locks up over the c wire, opens the locking circuit of CR to close circuit of calling lamp CL, and connects relay Br to the b wire which it also closes. The operator announces the selected junction and displays number over the order wire shown at CCF, Fig. 2, to the distant manual operator who plugs in, a lamp in her cord circuit being lit by battery over Br, Fig. 1, and the b wire to verify the junction. The manual operator completes the connection and Br energizes over the called loop. Registration of a four-digit number. The first digit is registered by RIO as before but in passing position 2¥, relays Dar, Dbr, Dcr do not pull up since this digit is always odd. In position 7“, 8¢ a circuit for sequence switch R is closed over cam C, back contacts of Dar, Dbr, and cam P so that the swith proceeds to position 10. In position 9¢ relays Mar, Mbr, Mcr pull up and store the digit as in the case of the second digit of a five-digit number. Release of register equipment. When the call has been taken by the manual operator, the semiautomatic operator presses key BDS to energize relay Rr which closes a circuit for switch R to move it to position 18. Switches R10, Ru now return to normal and R moves to position 1. Supervisory signals. The temporary bridge, herein before referred to, for controlling the automatic switches is given in position 14 to 16¢ of sequence switch R and extends over terminal a, contacts, of Ber, cam H contacts of Prr and terminal b. Release of junction. The calling subscriber releases the automatic switches and removes ground from the incoming c wire in Fig. 1, thereby releasing Abr. If the called subscriber has hung up, the junction is' free for further calls. If not, Br remains energized over his loop to hold open the battery connection to the c wire whereby preventing seizure of the junction until he has hung up. Premature release by calling subscriber. If this occurs when the lamps of the call indicator are lit (position 17), relay Crr, hitherto shortcircuited over contacts Bcr, cam G, terminal d and ground on the c wire, pulls up and energizes Glr to move sequence switch R to position 18 with the results previously described. Incomplete dialling; defective apparatus. arrangements for dealing with. If the calling subscri