Specifications

XT55 Hardware Interface Description

Confidential / Preliminary

mo b i l e

XT55_hd_v00.02 Page 29 of 116 17.03.2004

3.3 Power up / down scenarios

In general, be sure not to turn on GSM/GPRS part of the XT55 module while it is out of the

operating range of voltage and temperature stated in Chapters 6.2 and 6.3. The GSM/GPRS

part of the XT55 would immediately switch off after having started and detected these

inappropriate conditions.

3.3.1 Turn on the GSM/GPRS part of XT55

The GSM/GPRS part of the XT55 can be activated in a variety of ways, which are described

in the following chapters:

· via ignition line GSM_IGT: starts normal operating state (see Chapters 3.3.1.1 and

3.3.1.2)

· via GSM_POWER line: starts charging algorithm (see Chapters 3.5.4 and 3.3.1.3)

· via RTC interrupt: starts Alarm mode (see Chapter 3.3.1.4)