Cordless telephony within a building and the like, between a central unit and a mobile handset, uses multiple subscriber numbers in calls to trigger given actions on receipt

摘要

A fictitious digital call number as a multiple subscriber number (MSN) is used as a calling line identification presentation (CLIP) element in a call from the central unit to the mobile handset in the downlink direction. It is recognized at the handset to trigger a given action. A call from the mobile unit to the central unit with an alarm information in the uplink direction is through dual tone multi frequency (DTMF) and keyed as the fictitious digital call number. The system uses a telecommunication installation (15) and a base station (18).