Serial Port - Sierra Wireless AirLink GX Series Hardware User's Manual

AirLink GX Series Hardware User Guide
AirLink GX gateway
I/O Circuit
Pin 4 is normally at 3.3 V,
but is pulled low
when activated.
38
• As a digital output, it can trigger an alarm, siren, door lock or open a valve or
a switch. Pin 4 is an open collector transistor output normally at 3.3 VDC.
When triggered, it is pulled to low.
3.3 V
Voltage supply
51 k
internal
pull up
Figure 2-22: Digital Output Operation
Note: Some solenoids/relays include a flyback diode built into the unit. For those that do
not, Sierra Wireless recommends a flyback diode with a voltage rating at least double the
relay voltage and a current rating at least double the relay ON current to avoid damage to
the GX input. A common 1N4007 will work for most applications. See
page 42.
The initial state of the digital output when the gateway is rebooted is configurable
in ACEmanager.

Serial Port

You can connect the GX Series gateway's 9-pin serial connector directly to most
computers or other devices with a standard straight-through cable. This connector
is used for gateway configuration and debugging.
This connector complies with the EIA RS-232D specification for DCE equipment.
The output driver levels swing from -7 VDC to +7 VDC with normal loading.
Note: If you have a DCE device, you need to use a null modem cable.
CL+
Flyback diode
CL-
External Solenoid/Relay Circuit
(Exact voltages and configuration
depend on the actual system design.)
COM
NC
NO
Table 2-7 on
4114008