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AirAura X1 / Dec 2016
A P P E N D I C E S
GPO – General Purpose Output
AirAura X3 provides four General Purpose Output (GPO) circuits that may be used in
a variety of ways. Like the GPI circuits, the GPO interface utilizes optoisolators in order
to provide high electrical isolation from the outside world.
Unlike the GPI circuits each of the GPO’s has completely isolated return circuits – that
is, unlike the GPI port they do not share a common return. Because of this each GPO may
be used as the end user chooses without regard to cross coupling between unrelated exter
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nal circuits.
The optoisolators on the GPO interface protect internal AirAura X3 circuitry from
voltage up to 350 Volts AC or DC. Because of the optoisolator’s “AC” rating, the polarity
of external circuit polarity is unimportant and therefore the GPO pins are simply defined
as “Source” and “Return.”
The MAXIMUM permissible load current is 100 milliamps (0.10Amperes).
The four GPO ports on AirAura X3 are hard coded in software to provide the following
status outputs:
GPO Number
Usage
Source Pin
Return Pin
One
Analog Audio Fail
2
6
Two
Digital Audio Fail
3
7
Three
Overtemp (>50C)
4
8
Four
General Failure
5
9
Note that the GPO DB-9 connector pin 1 has no connection.
Please see the next page for a suggested way to interface the X1’s GPO circuitry.
GP Output #1
– Becomes enabled on an Analog Audio Failure.
GP Output #1
– Becomes enabled on Digital Audio Failure (either AES3 or WheatNet-IP).
GP Output #2
– Becomes enabled if the CPU Temperature reaches 50 deg. C (122 deg. F).
GP Output #3
– Becomes enabled upon a General System Failure.
The pin assignments for the rear panel DB-9 GPO connector is as follows:
