Circuitry for abbreviated dialling PBX - has storage area in programmed memory with common control which reads out onto trunks and junctions

摘要

The design is for a telephone exchange, primarily PABXs, with an abbreviated dialling facility. The complete numbers are stored in an exchange store, in the common control equipment, and when accessed are read out directly onto the appropriate trunks. A central store (CSP) contains the main network numbers and/or the numbers of other extensions. When accessed it reads out the required number onto a signalling wire (QUe,NAL). External network and PABX numbers are stored together. The first part of the address code, for accessing the store, contains an indication code signifying the direction, i.e. internal or external, and method of forward transmission for the number to be output immediately from the store (CSP). The indication code is in hexadecimal format. Telephones (Tln) are connected via peripheral circuitry (TS) to the switch block (KF). The external junction circuits (OVSt,QUe,NAL) are also connected via peripheral circuitry (AUe,Ue) to the switch block (KF). All peripherals and the switch block are connected for two way transmission to the common control (ZVE) containing the number store (CSP).