Selecting Telephone Antenna, Function

Selecting Telephone Antenna, Function






A GSM (global system for mobile communication) is required for transmitting a TELE AID emergency call telegram (TELE AID emergency call or telediagnosis), for completing a voice connection or for simply making a phone call.

For normal telephone calls it is the CTEL antenna (A2/22). This antenna can be damaged in the case of an accident (e.g. rollover). The antenna could also have another defect. TELE AID emergency call/telediagnosis is no longer possible then. To ensure that this never occurs, the TELE AID backup antenna (A2/50) is installed in addition to the CTEL antenna (A2/22). This is installed at a location which is largely protected against crash ahead of the roll bar, and is used only if required. For this purpose the telephone transmitter/receiver and TELE AID, D2B (A35/17) has two GMS antenna inputs to which the corresponding active antenna is switched through to the telephone transmitter/receiver unit.

NOTE: The telephone transmitter/receiver unit is integrated in the telephone transmitter/receiver and TELE AID, D2B (A35/17).

As long as no emergency call is triggered the CTEL antenna (A2/22) is always active. In the event of an emergency call the CTEL and TELE AID transmitter/receiver, D2B (A35/17) checks the signal level of the CTEL antenna (A2/22). If it is not sufficient it checks the level of the TELE AID substitute antenna (A2/50) The antenna with the higher signal level is used for radio connection (see structogram).