Patent GB-346714-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone exchange systems
IPC: H04Q3/58
Filed: 1930-01-15
Abstract: 346,714. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., Columbia House, Aldwych, London.- (Hatton, W. ; 18, Rue Boudewyns, Antwerp, Belgium.) Jan. 15, 1930, No. 1479. [Class 40 (iv).] In a rotary type exchange having access to two satellites, each having a capacity of 100 lines, junction selectors are provided in parallel with the rotary exchange final selectors which route calls to the required satellites in response to the normal control of the register translators. The units digit is stored by the junction selector either unaltered or with ten impulses added, depending on whether the hundreds digit is odd or even and the call is routed to either one or other of the two exchanges dependent on whether the translated units digit is under or over 10, the units digit being retransmitted in its original form. The junctions to the satellites are both-way circuits and repeated metering at the satellites is provided. Seizure of junction finder and storage of digits. When the junction finder circuit is seized C energizes and, when the fundamental circuit from the register controller closes, A operates followed by D. The common start relay S of the control circuit pulls up energizing relays SC which in turn complete circuits for magnets PF of the all idle control circuits having access to the junction finder. When one of the switches PF finds the calling finder, At operates and locks in series with Ah. Ct pulls up and the sequence switch steps to position 3, relay H energizing as the switch passes position 1¥, and relay Fl as it passes position 2¢. Relay H switches the calling circuit through to the control circuit, relay A now holding in series with H. The interrupter INT1 starts and connects interrupted ground, via its cam B1, first to Ac, which locks in series with Bc, and then to relay P (via fl3). At each interruption of B1 relay P connects earth to the fundamental circuit to step the register in the register controller and also connects earth to magnet P10 to step the ten's register. When the tens register in the register controller had been counted out Fl releases opening the circuit of P and allowing the sequence switch R to move to position 6“, relay Fl energizing in position 5¥. The interrupter INT1 restarts, energizing Ac and Bc as before, and P repeats the impulses to the units registers in both the register controller and the control circuit. If the hundreds digit was odd the number stored by the units register PU is between 11 and 20, and this fact is used to determine to which exchange the call shall be routed. When 10 impulses have been stored in PU wiper a completes a circuit for Ts and, when the eleventh impulse has been stored, Oh energizes and locks. Relay Oh changes the stop position of the units register from the eleventh to the tenth contact and changes over the test relay Bt from wiper ps4 to wiper ps5. When the register controller units register has been counted out Fl releases and the sequence switch steps to position 7“. Relay Ts releases imposition 6“ and earth is removed from pf4 to release H and A, D remaining operated in series with B which now pulls up. The shunt across C is removed allowing the preceding selector to move to the speaking position. Selection of junction and transmission of digits. The junction finder PS starts to hunt for an idle junction to the exchange required, the selection depending on whether search is made over ps4 or ps5 determined by the condition of relay Oh. When a free circuit in the required direction is found Bt energizes stopping hunting and locking in series with Bh. The sequence switch moves to position 9“, Ts reoperating and locking as the switch passes position 8“. An out-impulsing circuit is now completed to the distant exchange and the common dial interrupter INT2 is started connecting interrupted ground to its cam B2. Relays Ac and Bc energize and P responds to the impulses sending them to the distant exchange and stepping the ten's register P10. When P10 reaches its home position Ts releases breaking the circuit of P to stop impulsing. The sequence switch now moves to position 13, Ts reoperating as position 12 is passed. The interrupter INT2 is again started, Ac and Bc operate and P repeats the impulses to the distant exchange and to the units register. Relay P releases when PU reaches its 10th or 11th position (dependent on whether Oh is up or down) and the sequence switch moves to position 17. Relay F energizes in position 16¥ locking to c1, switching through the connection, releasing At and Ah and connecting earth forward to energize Co to mark the both-way junction as busy. In the control circuit P10 and PU home in turn over their off-normal contacts and the sequence switch moves to its normal position releasing Bt, Bh and Oh to free the control circuit. Metering. In the 100 line step by step exchanges repeated metering facilities are provided. When the both-way junction is seized from the satellite Jl energizes followed by Is which closes circuits for the line finders in the rotary exchanges. When the junction is connected up Co energizes releasing Jl and Is and when the called subscriber replies earth on the fifth wire energizes Mo which locks to co2. Mc is connected to the fifth wire, and the b wire circuit is opened, the supervisory relay being held over mo4. Mc is slow to operate but when it pulls up it recloses the b wire. This short break in the b wire causes the operation of the metering start relay at the satellite. Release. At the end of the conversation Co falls away, Mo and Mc de-energize releasing the circuit. Calling party release is normally provided but forced back-release is arranged for. If the called party alone hangs up earth is removed from the 5th wire and Mc releases opening the b wire which releases the junction.