Digicom pocket GSM User Manual page 51

PocketGSM
Power on PocketGSM connecting the cable with the correct polarity:
pin 9: positive [from +5 to +32Vdc]
pin 10: negative [GND]
The modem has a special protection in case you accidentally invert the polarity.
CHARACTERISTICS OF GPIO CONTACTS
PocketGSM supports:
4 digital inputs (two logical states: ON/OFF);
2 analog inputs;
2 output open-collector.
Digital Inputs
Two status are supported for each input: open or closed to
ground.
It is necessary connect only a free contact (without voltage)
between the input pin (pin 6, 5, 4, 3) and the ground pin (pin 10).
DIGITAL INPUT CHARACTERISTICS
Permitted status:
Analog Inputs
Two Analog to Digital Converter are available on the PocketGSM. These converters have
a 10 bit resolution, ranging from 0 to 28 Vdc.
ANALOG INPUT CHARACTERISTICS
Resolution
Input signal range
To read the value, use AT+ADC command. Send AT+ADC=1 command and read the
value with AT+ADC? command.
Input open
Input closed to ground (GND)
10bit
From 0 to 28Vdc
4.31
AT Commands