Patent GB-467442-A (GB)
Title: Improvements in telephone or like systems
IPC: H04Q3/00
Filed: 1935-12-16
Abstract: 467,442. Automatic exchange systems. AUTOMATIC ELECTRIC CO., Ltd., SAVILLE, W., and WILLIAMS, A. H. Dec. 16, 1935, No. 34932. [Class 40 (iv)] A mechanical impulse repeater, e.g. are. generator of the kind described in Specification 458,095, is controlled so that the initiation of the retransmitting operation is dependent on external conditions. In one arrangement, Figs. 1 to 3, the device is used for storing and retransmitting, if necessary, the discriminating digits dialled by a subscriber on a satellite exchange in which a junction is only taken into use if necessary. In this case retransmission is initiated by the switching relay of the junction selecting switch. In another arrangement, Figs. 4 and 5, the device forms part of an outgoing repeater which is the same as that described in Specification 464,058 except that retransmission is delayed until a signal is received from the incoming exchange. Other applications are summarized below. Discriminating selector-repeater--establishing main office call. The parallel dialling relay C energizes the marking magnet MM of the regenerator, to prepare it for reception, and a sluggish relay IP which energizes IS in series with the sending magnet MS. MS is not operated in this circuit. The vertical magnet VM and the regenerator stepping-magnet MR respond to the first digit and, on the relapse of C, a circuit is made for JD if the digit indicates a call via the main office. JHM then drives its switch in search of a junction under control of K. If the first digit is inconclusive, the relapse of C energizes the release magnet and, on the completion of release, AD pulls up in two steps and locks. The vertical magnet and magnet MR then respond to the second digit and if the call is to be extended via the main office JD is operated as before. When K switches through, JA operates and, BY having been operated previously over MN1, and mm, IP is shunted out and releases IS which after an interval, energizes MS to restore the pin in the disc P that has previously prevented the movement of the sending disc S. MS opens springs ms and IP then operates again re-energizing IS and releasing MS whereupon disc S rotates under spring control until the first pin displaced by the marking magnet engages the re-set pin. During this movement, impulses corresponding to the first digit are sent to the main office by springs IMP. When the two pins engage, IP is again shunted and on the relapse of IS the second digit is retrans. mitted. Subsequent digits are sent in a similar manner. At the end of the last digit, the disc S overtakes the disc R, the springs MN1 open and BY, IP, IS fall back. Discriminating selectorr e p e a t e r-establishing local call. If the number dialled begins 77, the selector - repeater drops back as previously described after the first 7 and after the second (AD being locked up and terminals X, LB strapped together) a circuit is made for LC which locks and operates the release magnet. When restoration is complete, LD locks and changes the circuits of the switch so that on the reception of the third digit the selector repeater hunts in the selected level by interaction with relay G and no operation of the junction hunting switch takes place. When an idle switch is found, H switches through and shunts IP to restore the regenerator to normal. Normal release. On the relapse of A, C operates momentarily energizing IP which holds the switch guarded temporarily after the relapse of B. Operation of C also delays the release of the switching relay K and of relay JD. When it falls back, the relapse of K unlocks JA but the junction remains guarded temporarily by JB to give time for the distant switches to release. Premature release. If release is premature, e.g. because on all trunks busy condition is met, the regenerator is run down on the relapse of C which releases IP. IP disconnects ground from the private wire to release the preceding switches but the guard is at once replaced by IS which remains de-energized throughout to enable the regenerator to be restored rapidly. Metering. The operation of D, DD, when the called party replies, reverses the connection of the line relay and energizes H to initiate the operation of S and Z relays DA, DB. During the Z pulse the meter may be operated a number of times depending on the zone metering lead selected by the right-hand vertical wiper, the relay J responding to the metering impulses and repeating them over the private wire. Where AD has been operated, as with local and short distance calls, only one operation of the meter is given. Two-way working. In incoming calls, JB is operated from the incoming selector and marks the junction busy. In outgoing calls JA .. JC disconnect the incoming selector when K switches through. Indicating coin-box calls to operator. Coinbox substations are distinguished by the connection of a tone current to the private wire. This current reaches the talking circuit via QF and is not appreciably shunted by relay TI, over which the selector repeater is guarded, owing to the high impedance of that relay. Faults. Relay TI over which the private wire is grounded when the circuit is seized connects TP to a pulse wire IS and unless TP is prevented from operating or is released by AD or by the off-normal springs an alarm is given over ST and B is shunted out. An alarm is given also if the regenerator is off-normal for an undue time without transmitting. Outgoing repeater, Figs. 4 and 5. Relay SW delays sending until a signal is received from the distant office. When the distant finder switches through, relay I which at this stage has a local battery connection pulls up over the + wire and energizes SW which locks up. SW connects I in the usual supervisory bridge (in which it is short-circuited at this stage by BY) and shunts out IP to initiate the transmission of the stored digits in the manner described in Specification 464,058. Further applications, not described in detail. The mechanical regenerator may be used to replace the numerical registers in a code translating register controller. It may be used to store the whole number in a system in which a call on finding the normal route busy is extended over an alternative and more circuitous route. In another arrangement a subscriber of an automatic P.B.X. needing outgoing service is given access to an idle mechanical regenerator which takes the whole wanted number and is associated with an outgoing junction by the operator when one becomes available. In another arrangement the regenerator stores some or all of the digits dialled by the subscriber and controls ten-point uniselectors to mark and start large capacity finders in the proper numerical groups in turn.