Print=out circuit for data supplied by telephone exchange - uses existing serial data link with service desk

摘要

A print-out unit circuit requires a min. amount of special wiring to the exchange, while at the same time covering a wide range of information from equipment performance for maintenance purposes to statistical and financial data for collection of call fees. An existing system transmits data from a central exchange (SZ) to an 'enquiry and service desk' (BAP) via a single serial data bit link (DK) for the bi-directional transmission of information. This existing line is also used for the purpose of connecting a print-out unit (DR). To this end such a unit can share the series/parallel conversion unit (SBA) which the enquiry and service desk has in any case, and which produces discrete data words in parallel bit format. Dependent on the nature of the data, these may additionally be displayed in a unit (AAF) responsive to specially coded clock pulses selectable at the enquiry and service desk. Such a selection may also be preset at the exchange.