Selecting telephone antenna, function

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

When making normal telephone calls the telephone antenna is used for this purpose.

The telephone antenna depends on the model

Model 129: Rod antenna (A28)

Models 202, 208.3, 210, 220: Telephone antenna (A2/49a1)

Model 215: Telephone antenna (A2/22)

This antenna can be damaged in the case of an accident (e.g. rollover). TELE AID emergency call is no longer possible then. To prevent this in any case the TELE AID substitute antenna (A2/50) is installed in addition to the telephone antenna.. This antenna is located at a crash-safe location and is only used if required. For this purpose the emergency call system control module (TELE AID, A35/8) has two GMS antenna inputs and one output; the corresponding active antenna is switched through to the telephone transmitter/receiver (A35) via this output.

Level test:

A2/50

Transmitting/receiving

via A2/50

Transmitting/receiving

via A2/49a1

Level test:

A2/49a1

Level

sufficient

Level comparison:

A2/50>A2/49a1

No

Yes

Yes

No

?

Tele Aid

Emergency call

?

Structogram: Antenna selection with TELE AID emergency call

As long as no emergency call is triggered the telephone antenna is always active. In the event of an emergency call the emergency call system control module (TELE AID, A35/8) checks the signal level of the telephone antenna. 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).

 The telephone antenna inputs on the emergency call system control module (TELE AID, A35/8)are equipped with identical sockets.Always ensure that the antennas are installed correctly (color marking).