Axia Element - Chapter Three: Configuring GPIO; GPIO Port Definitions

3: Conguring GPIO • 21
©2008 Axia Audio — Rev. 3.0
Chapter Three:
Configuring GPIO
Since the days of rotary-switch source selectors, it’s
been a challenge to properly route machine logic along
with audio. Some complicated schemes have been de-
vised over the years, but broadcasters wanted a simple,
fast way to associate logic with audio in a routable en-
vironment.
Since the Axia IP-Audio system was designed as
a true computer network, we were able to start with a
clean sheet of paper to design the first truly routable ma-
chine logic/audio interface. Unlike conventional logic
connections which require each command circuit to be
wired individually, Axia sends machine controls over
the same Ethernet your audio travels on, further reduc-
ing infrastructure, cost and tedium.
Along with controlling external audio devices,
Element’s GPIO interface also includes logic commands
for routine studio/control room operations such as tally
lights, monitor muting, On-Air lights and more.
This chapter explains how to set up Element GPIO
to handle these functions. (We assume you’ve already
read the GPIO Node User’s Manual, familiarized your-
self with its controls, and assigned it an IP. If not, we
strongly recommend you do so, as this chapter is not
designed to be a comprehensive primer.)
Note: Your Element ships with a combination
GPIO Node/Power Supply that also contains the
Element CPU. These units are convection cooled,
and we strongly recommend that, when rack-
mounting these units, you leave at least 1RU of
space above and below the GPIO Node/Power
Supply to ensure adequate ventilation.
GPIO Port Definitions
Each Axia GPIO has eight DB-15 connectors on its
back panel. Each connector can be associated with a de-
vice in your studio, and provides five opto-isolated in-
puts and 5 opto-isolated outputs per device for machine
control, lamp drives and remote channel controls.
GPIO ports are programmed to support several dif-
ferent types of devices. How does a GPIO port “know”
which type of device is assigned to it? Well, there’s a
little bit of magic involved.
Back in Chapter Two, when you constructed a Source
Profile for a telephone hybrid, you defined the source
type (see “Adding Backfeeds and GPIO to a Source Pro-
file,” p. 12). This is important, because when that source
is assigned to a console fader, Element uses this Source
Profile selection to tell the GPIO Node what sort of com-
mand to send to the attached device..
If Element “sees” in the Source Profile that the as-
signed device is a microphone, it tells the GPIO Node to
send logic for On, Off, Remote Mute and Remote Talk
commands on the appropriate pins. If it “sees” a line
input, it tells the GPIO Node to send Start, Stop and
Reset commands, plus closures for Ready lights, etc.
Axia GPIO ports can deliver command sets for the
following devices:
Microphone (Operator, Guest or Producer)
Line Input
Codec
Telephone Hybrid
Computer Playback Device
Control Room Monitor
Studio Monitor
Profanity Delay Device
Accessory Button Panel Device
The next few pages contain tables that explain what
function the pins provide in each different device mode.
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