Patent GB-499783-A (GB)
Title: Improvements relating to telephone systems
IPC: H04M3/523
Filed: 1937-07-29
Abstract: 499,783. Exchange systems. SIEMENS BROS. & CO., Ltd., and HENSLER, B. A. July 29, 1937, No. 21005. [Class 40 (iv)] In a system in which an operator or common apparatus, e.g. a register-controller may deal with more than one class or group of incoming circuits, a comparison is made between the existing conditions of two classes or groups, e.g. as regards the number of waiting calls or delay in dealing with calls, whereby the efforts of the operator or common apparatus are automatically directed to the class or group which most urgently requires attention. The invention is described in connection with a system employing call-distributing and queueforming arrangements as described in Specifications 439,318 and 468,722. Different groups of incoming circuits are distributed to different operators or groups of operators, one or more omnibus operators being. called in to deal with calls in the group having the greater congestion or delay. More particularly, each pair of groups 1 and 2, 2 and 3, and so on, has an associated omnibus position so that calls in any one group may be dealt with at either of two omnibus positions. It will be assumed that Figs. 1 and 2 show the queue-forming circuits of group 2 and that Fig. 3 shows a part of similar circuits of group 3. Congestion or delay in group 2 may be dealt with by an omnibus position of groups 1 and 2, or groups 2 and 3, the control circuit for the groups 2 and 3 position being shown in Fig. 4. The comparison of the states of two groups may be made by comparing the indications of devices for ascertaining the number of waiting calls in a group as described in Specification 454,739 or by a differential contactmaking meter having its windings fed over numbers of resistances dependent on the calls in the two groups, or by the arrangements described below. If the number of waiting calls in the two groups is the same, delay beyond a predetermined time determines which group is attended to. Call distributing and queue-forming circuits. The distributing, queue-forming, and delaytiming circuits are as described in Specification 468,722 with the following modifications. The distributers (not shown) have outlets after the first or overflow outlet which are, in order, 10 outlets to the lamp-queue display circuit, a control outlet, outlets to the corresponding ordinary operator for the group, and two groups of outlets to the omnibus positions which may deal with the group. In order to accommodate the increased size of the queue, a relief' switch RB is provided for the queuecontrolling switch RA and has its bank contacts connected in the lamp multiple at X, Fig. 1, in rotation with the banks RA6, RA7, the back-stroke magnets of the two switches being kept in step by relay SY operated over inter-oonneoted banks RA2, RB1. When a caller in the queue abandons the call, it is arranged that the distributer concerned is held until it is released from the queue in the normal course of events whereupon the queuecontrolling switches are automatically given an extra step to release the next distributer (if there is one) from the queue. When the distributer of the abandoned call is released, it transmits a momentary signal over PW to PU which locks up and when the switches have taken the usual step and released ST, relay PU, having contacts with different release periods, releases and makes a momentary circuit to re-operate ST whereupon the switches take a further step. As the queue is filled up, wires L1-L10 are grounded in turn to operate relays LA-LJ which in turn light display lamps over circuits LW1-LW10 and control queuecomparison circuits as will appear later. Omnibus position control circuit. Relays LL and LR, Fig. 4, are control relays corresponding to group 2 (Figs. 1 and 2), and group 3 (Fig. 3) respectively, and DL, DR are the corresponding delay relays operating on excessive waiting time. Relay LR is connected to ground over successively opened parallel. contacts la3-lj3, Fig. 2, of the group 2 queue and successively closed contacts la4-lj4 of the group 3 queue so that it operates only if queue 3 exceeds queue 2. Similarly, LL operates over contacts la5-lj5, Fig. 3, and la2-lj2, Fig. 2, if queue 2 exceeds queue 3. The contacts la4-lj4 and la5-lj5 in Fig. 2, are similarly associated with queue contacts of group 1 and connected to the omnibus control circuit of groups 1 and 2. By staggering the cross-connections CCN, relays LL, LR operate on any desired ratio of waiting calls. The relays LL, LR may operate over the above circuits only if neither or both the delay relays DL, DR are operated. Delay relay DL and the corresponding relay in the group 1, 2 omnibus control circuit are operated at the end of the timing period of valve VA operating as described in Specification 468,722, the relapse of anode relay AN connecting ground to wires DW and DWL. Whenever DL or DR operates alone it operates the corresponding control relay in a local circuit. DL, LL, LR give ground signals to a supervisor over leads DWD, MWL and MWR and LL, LR also ground leads SWL, SWR to light the corresponding queue display lamps at the omnibus position and cause connection of the assignment leads thereat to the start lead RC, Fig. 1. When there is any call in the queue, EN operated by ground on lead L1 puts ground on lead TQ to operate control relay LL over a second winding. This also brings in the omnibus position, but LL does not operate over its second winding if LR is operated indicating excess calls in group 3. It is also arranged that if there are no waiting calls, the assignment leads from the omnibus position are connected to start lead RC. Relay W, Fig. J, operated in parallel with DL connects ground pulse lead FE to CAL to flash group lamps at the ordinary group 2 positions and at omnibus positions switched to deal with group 2 calls. The ground normally connected to lead CM, Fig. 1, and providing test potential for distributers before a queue is formed is disconnected when EN pulls up over the first queue lead L1. Lead CM Fig. 1, is connected to the connecting circuits, at ordinary group 2 positions, to wire CML Fig. 4, and to a wire at the other omnibus position corresponding to wire CMR, Fig. 4, wire CM, Fig. 4, being connected to the connecting circuits of the other omnibus position. Wire CMR, Fig. 4, is connected to the CM wire of group 3.