Patent GB-1281168-A (GB)
Title: Manual switch-board arrangements in telephone or like switching systems
Inventor: BRADLEY IAN ASHE
IPC: H04Q3/545
Filed: 1969-04-12
Abstract: 1281168 Automatic exchange systems PLESSEY TELECOMMUNICATIONS RESEARCH Ltd 2 April 1970 [12 April 1969] 18865/69 Heading H4K Manual boards, with connect circuit arrangements and information display devices for each call given assistance, have only one appearance on the outgoing side of an exchange network for each call assisted, the network being such that, in order to connect a calling party to a wanted party, connections are set up concurrently from the calling party's appearance on the incoming side of the network to the manual board appearance and to the wanted party's appearance on the outgoing side of the network. The connection of the two parties and the operator in star formation is referred to as an overlay connection. Such a connection of the operator makes it necessary for line splitting to be effected in the incoming and outgoing junction circuits. Each of six connect circuit arrangements on a manual board may have a corresponding appearance on the outgoing side of the exchange network but, with stored programme control, the six arrangements may be served in common by one such appearance, data files being kept of all necessary particulars relating to each call being serviced by each connect arrangement and associated display so that connections are switched to either appearance as and when operator action so requires; operation of each information display is effected by command from the processor and does not depend on the connection of the operator to the network. Exchange network and control.-The network is comprised of reed relay matrices in the stages shown in Fig. 1, the first and last two stages being mirror-image concentrators, the middle three stages being called dispersors and providing battery feed and hold relay function from circuits between the second and third dispersor stages. Subscribers have appearances on both sides of the network. Multi-voice-frequency receiver / senders and sender / receivers MVF.RX/S and MVF.S/RX are accessible at the outlets of the expander and the inlets of the concentrator stages, respectively. So-called revertive interface circuits couple inlets of the network so that a manual board by connections back and forth across the network can give service to an outgoing junction. Conference connections are provided by an operator who successively calls up parties nominated by a convener, the outgoing side appearances of the parties being connected to a conference equipment which has a number of appearances on the incoming side; the convener may be connected by a special terminal COT on the outgoing side. The common control employs processors P1 to PN each working to a fraction of the overall system programme as described in Specification 1,243,464. The processors communicate with processing system peripherals, such as stores and tape punch and readers, by way of a looped highway system DPH and the highway stations HS; communication with network control peripherals such as scanners, markers, and manual board control, by way of a looped highway system TH.  Manual board equipment.-Operators' positions are governed from the processors over a highway station HSMB and a suite control unit as shown in Fig. 6, each unit having one channel to relay messages indicating the condition of keys to the processor and a second channel receiving messages from the processor to control the lamp displays on the manual board. The manual board keys are non-locking, any locking that may be required being effected by programmed system response. Each board, Fig. 5, not shown, has a conference, speak-to-monitor, block pip-tone, route information, and A and B party keys used in common for all calls. The keys have integral lamp units. A ten key number sender has an associated cancel/release key to clear a wrongly connected party. A preset button is used to signal the position available, it being necessary to re-establish this signal following the clearance of all calls wanting service at any time. Each connect circuit position has speak and monitor keys with integral lamps, and has a call timer with start switch, and has a set of engaged, timer, and calling and called answer lamps. Operator assistance, procedures.-The manual board processor P7, interacting as shown in Fig. 2 with the other processors, pursues the functions illustrated in Fig. 7 in order to analyse key operations and return lamp signal indications. Operator's procedure is set out fully with an indication of the general nature of the programme responses involved for a switchboard in which the connect circuit arrangements share two appearances on the outgoing side of  the network, records being kept to enable the setting up of a circuit to any particular call connect arrangement required by operator action. This programme operates as though all connect circuit arrangements have individual exchange appearances and gives rise to description in terms of "fictitious connect circuits". Demand call procedure connects a calling incoming side junction to an operator's position and, when call particulars are taken the wanted subscriber's number is keyed into a register of the processing complex and an "overlay" connection is set up to the wanted outgoing junction, line splitting for A and B party supervision being effected in the incoming side junction as directed by the processor in response to operator key signals. Operation of a speak key while a speech connection exists on another operator connection causes a programme interlock to switch the first such connection from speak to monitor. Call timing is started by the operator in response to called party reply and is stopped automatically when the processor responds to release. Revertive call procedure, in which the caller clears and the operator undertakes to call back with the wanted connection, is initiated by setting up a connection from the operator to the first incoming side appearance of a revertive interface circuit and at the same time making a register available for operator's keying of the wanted number. The wanted outgoing junction is connected to the second appearance of the revertive interface circuit. The calling party is then keyed for and the first appearance of the revertive interface circuit is connected to the calling party's outgoing junction appearance such connection being in common with that made from the first appearance to the operator. Line splitting is effected in the outgoing junctions. Conferences are set up on instructions from a convening calling party. On operation of the conference key the convener may be connected to the conference circuit by use of the conference outgoing terminal COT, Fig. 1, other parties to the conference being collected one-by-one as revertive connections of operator to outgoing side appearances by way of successive appearances of the conference circuit on the incoming side of the network. After giving conference particulars the convener may retire and be called up to join the conference revertively.