Siemens Terminal TC35 - Manual (Page 29)

27
Startup
In its energized state, the GSM module
provides the supply voltage (VDD). VDD
ensures that the switching regulator
remains on, even when its closing condition
is lost (i.e. IGT_IN=low).
Explanation:
VBAT=operating voltage for the GSM
module
VDD=supply voltage from the module
Activation of the RS232 control line DTR
The TC35 Terminal can be switched on in the
same way as via IGT_IN by activating the
RS232 control line DTR (high signal).
Note
The TC35 Terminal is switched on
immediately using the recommended plug-
in power supply unit (see the above
explanation on startup).
Switching off /
resetting the
Terminal
The Terminal can be switched off in two
different ways:
Using a software command by means of
an AT command
A software shutdown via an AT command is
always advisable for a controlled shutdown
of the TC35 Terminal. In this case, the GSM
module signs off before the watchdog
condition results in the specific switching off
of the supply voltages.