Infinite Peripherals SCOM-100 - Manual (Page 9)

SCOM-100, User guide 9
Bridge Vcc to Vex on the main SCOM-100 unit to power a limited number of I/O
expansion units (up to 4), as shown below. (Power is then internally wired through the
modular I/O expansion connector).
If the number of expansion modules is more than 4, an external power supply source
must be connected to the power connector screw terminals of each expansion module,
as shown below, and the Vcc to Vex on the main SCOM-100 unit must not be bridged.
Note: The Vex pin must not be connected when an external power source is connected
on the expansion modules because the main SCO-100 unit will be damaged.
2.6 GSM antenna
An external GSM antenna should be used for locations with weak signal strength.
SCOM-100 utilizes an SMA plug connector to connect a GSM antenna.
The GSM antenna must be of appropriate frequency to cover the frequency band of
your GSM provider’s network.