Fig. 4-1 Timing Of Power On/Off Signals - Siemens M20 Terminal Technical Description

Siemens Information and Communication Products
4.3.2 Power on/off
Signal Function
IGNITION Switch on
POWER_ON Power-on indicator
RES# Reset indicator
:
Note
1
) Level range: 0 < IGNITION < 6.2 V, (maximum voltage: +/-50 V). For additional information see
.
on page 200
2
) See

Fig. 4-1 Timing of power on/off signals

To turn on the M20, connect IGNITION to the voltage specified in the table above. The device will then keep running
even if a voltage < 0.6 V is applied to IGNITION or the device is left disconnected. To turn off the M20, use the corre-
sponding AT command (AT^SMSO, see Chapter
Note: if IGNITION is connected to a fixed voltage > 1.3 V, the M20 cannot be turned off with an AT command.
POWER_ON indicates that the microprocessor of M20 is supplied.
RES# level High indicates that the microprocessor of M20 is supplied and working.
Note: RES# also can be used as 2.8 V reference level for applications of the M20.
For additional information, see
Uswitchon
Uswitchon-0.7V
2V typ.
Fig. 4-1 Timing of power on/off signals
Version 8 dated 15.03.00
I/O
I
O
O
case IGNITION > 2.7 V level = IGNITION – 0.7 V.
5.7 "Siemens-defined AT commands for enhanced functions" on page 111
Fig. 4-1 Timing of power on/off signals
IGNITION
RES#
2.8V
300ms
POWER_ON
Level Comments
1
) IGNITION >2.7 V for longer than 1 s switches on
2
) Load current < 300 uA
Note: may be unconnected if unused
2.8V Load current < 500 uA
Note: may be unconnected if unused
.
duration > 1s
Hardware interfaces
8.8.6 "Ignition line"
).
t
t
t
A
18