Patent GB-830615-A (GB)
Title: Improvements in or relating to automatic telegraph exchange systems
IPC: H04M3/523
Filed: 1956-06-22
Abstract: 830,615. Telegraph exchange systems. PHILIPS ELECTRICAL INDUSTRIES Ltd. June 22, 1956 [June 27, 1955; Sept. 14, 1955], No. 19432/56. Class 40 (3). In an automatic telegraph exchange system in which the lines for the various directions are connected to the outlets of a number of selectors, an individual waiting outlet provided for each direction has an associated waiting circuit, a plurality of selectors may be set to the waiting outlet corresponding to a desired direction and each selector has separate control means comprising an arrangement for determining the time a selector has been adjusted to a waiting outlet and means which is operative when a line in a desired direction becomes free to adjust to that line the selector which has been waiting the longest time, the line being marked by the waiting circuit concerned. When a message is ready to be transmitted from the exchange, a transmitter TZ, Fig. 1, engages an associated connecting device VS co-operating with a selector RK which is one of a number having multipled outlets serving groups of lines, such as UL11, UL12 and UL21, UL22, representing outward extensions of the connection. Contacts on the selectors RK are allotted to the various groups of outgoing connections and are connected to waiting circuits WS1, WS2 which are connected to the outgoing lines UL11, UL12 and UL21, UL22 respectively. When the circuit VS has been connected through a finder ZR to a free register REG, by a circuit AL which is such that only one selector can be operated at a time, the coded address of the message is converted to a signal passed to the allotter circuit AL common to all outgoing groups of lines, and the register is operated to mark the appropriate conductor MR1, MR2 ... associated with the desired outgoing line and causes the selector RK to be adjusted to the corresponding waiting circuit WS1, WS2, .... The register becomes disengaged and the selector RK retains its position until a line in the desired direction becomes free. Each connecting circuit VS includes a timing circuit for determining the time its selector has been waiting. When a line becomes free, the corresponding waiting circuit WS1, WS2 transmits a signal to the common allotter circuit AL which seizes the waiting circuit in question and also energizes a relay in each connecting circuit VS of which the selectors RK is adjusted to the selected waiting circuit. Under the control of the associated timemeasuring circuits, the connecting circuits VS mark the lines M1, M2, ... to the circuit AL in accordance with the time during which they have been waiting. The device AL tests the lines M1, M2, ... and having detected the one with the longest delay allots the corresponding connecting circuit VS which then adjusts its selector RK to the free line associated with the corresponding waiting circuit WS1, WS2, .... Detailed circuit arrangement, Fig. 2. When a connecting circuit VS has been engaged, a relay ST is operated and when a free register has been found a register relay RB is operated over line RG1. The relay RB locks over rb2, and over rb3 operates relay GR which at gr1 applies earth to the lead RG2 so that the register applies a marking potential to MR1 and a pulse over RG3 to operate a relay V which at v1 operates the magnet D to step the selector RK to the marked conductor MR1 by means of which a relay T is operated to open the circuit of the magnet D and actuate a relay P which at contact p1 opens the circuit of relay V so that the register is released. At p3 a circuit is prepared for a relay Q which operates over the released contact t1 when released contact v2 has opened the circuit of relay T. At contact q2 the relay W of the waiting circuit operates and closes contact w1. At contact p2, relay TA of the timing circuit TS is operated when contact si is closed and when si opens, the relay TB is operated in series with relay TA. At the end of a predetermined period, e.g. a minute, relays TC, TD are operated, and at the end of a further period, e.g. a minute, the relays TE and TF are energized. When a line becomes free its relay L is released so that at contact l1 a circuit is closed to a waiting circuit relay RA which operates, and locks up over contact ra2 and operates a relay H which at contacts h1, h2 operates relay B of all connecting circuits of which the selectors RK have been set to the waiting circuit WS and relay A. At contacts b1, a2, by means of a waiting circuit comprising relays AA, AB ... AF and pulses applied at contact ic, the relays AB, AD, AF are operated in succession so that the points M4, M3, M2 or M1, marked according to the operation of the relays TB, TD, TF of the various timing circuits, are tested in sequence. If the maximum time detected relates to the selector shown a relay KA is operated and at contact ka3 energizes a slow relay GS and at contact ka4 a relay S opening the waiting circuit. Operated contact gs1 energizes the relay V which steps the magnet D until the selector RK finds the free outgoing line of the waiting circuit selected. If the waiting times of two (or more) selectors are equal relays KA, KB, ... are operated and lock up. The relay V of the connecting circuit associated with relay KA is operated over operated contacts gs1, ka1, p1 so that the associated selector is operated, but the circuit of the relay V associated with relay KB is open at operated contact ka1 so that the selector of the connecting circuit allocated to relay KB cannot be operated. When the selector reaches the line marked by the closed contacts h3, l2, the relay T operates and at contact t1 opens the circuit of the magnet D. A circuit is also completed over contacts t1, q<1> for relay C which at c2 breaks the circuits of relays P, Q so that contact p2 disconnects the counting circuit TS and contact p1 releases relay V. When relay V is operated, the circuit of the relay B was opened so that the original locking circuit of relay KA was broken, but the relay KA remains locked over contacts v3, c1 until the operation of relay C opens the locking circuit. Over contact c3 the line relay L operates so that at contact l3 the selector RK connects the transmitter TZ to the line UL. At contacts l1 and/or w1 the circuit of relay RA is opened except for the case that a second line is free in the direction concerned and a selector is waiting at the circuit WS. In this case relay RA is held by the closed contacts l1, w1 and when KA releases, a relay of the connecting circuit such as relay KB, operates and via contacts gs1 (operated), kal (released), kb1 (operated) and p1 of the connecting circuit concerned operates its relay V to adjust the selector RK associated with the connecting circuit to the second free line. If relay RA releases, relay H of the waiting circuit releases so that contact h1 opens the circuit of the B relay of any selector set to the waiting circuit WS. When contact h2 opens, relay A releases and at contact a1 opens the counting circuit US. In the modified circuit, Fig. 3 (not shown), which is generally similar to that shown in Fig. 2, the chain circuit RS is omitted and the circuit AS includes relays associated with the registers and the magnets B, which in Fig. 2 are controlled by the operation of relay H, are operated when the selectors are moved to the position corresponding to the connection of the waiting circuit for a desired direction and the relay H is controlled by the B relays and a contact bank of the selector.