Operator reservation of lines in electronic telephone exchange - allows intervention in programme controlled process for manual operation

摘要

A system is esp. useful for private programme-controlled branch telephone exchanges. It allows the operator to intervene, reserving links for manual control. When the locking button (SPT) at the operator position (BPL) is engaged, a blocking element (SP) switches one contact (sp1), illuminating an indicator lamp (SPL) at the operator position, and a second contact (sp2). The second contact (sp2) makes two connections (pr1, pr2) in the programme control unit (PST), so that a relay (BSG), independently of the programme, signals the engaged condition for the corresponding exchange links, and reserves them for control by the operator.