GPIO
General Purpose Input Output (GPIO) has been a common function in radio studios for many years. Though AoIP has changed the way in which components interface with one another, logic states between gear remains widely depending on this legacy method of wiring.
From the beginning, Axia has endeavored to make the process of configuring GPIO as plug-and-play as possible, and the strategy used to achieve this has been to define behavior through the use of profiles. Each Source Profile (as outlined in Chapter 3) defines how the 5 GPI, 5 GPO, and 15 pin GPIO ports behave based upon how each is expected to be employed in a typical studio. Information about each Source Profile plus tables for GPIO ID and pin-outs are provided below.
Source Profiles
Source profiles include:
Line Input – Used for any general audio source.
Computer Player – Similar to Line Input, but with a different logic control commonly found with PC-based automation systems. For example, pressing the “On” button while the source is already in the “on” state triggers the next event in the automation.
Phone – Defines the source as a hybrid or broadcast phone system input. Single line phone hybrids commonly want the line to be seized when a state is changed on the console, such as when the channel is turned on or set to a preview state. A summed mono mix-minus is automatically created for the source, and controls for Telos products will be available.
Codec – Links to remote codecs often require a GPIO to trigger IFB communication and a dual mono mix-minus for the source consisting of one PA feed (right channel) and one talent feed with talkback (left channel).
Operator Microphone – This is the board op’s mic which often requires different GPIO functions than other studio microphones.
CR Producer Microphone – The in-studio producer’s mic may not have access to the console but often requires the same controls as the operator.
CR Guest Microphone – Used for any other mic in the control room.
Studio Guest Microphone – Similar to the CR Guest Microphone, but with different monitor muting requirements.
External Microphone – Used for any mic located outside of the CR or studio, this functions like a Guest microphone but without any muting logic.
Studio Feed – Typically a source that receives a backfeed and generates an IFB backfeed in return. This is intended for an external studio source for which you wish to create a talkback channel.
Record Mode – Provides GPIO control of the various Record button functions
External Timer Control – Provides GPIO control of the count-up timer.
V-Mixer – Controls the Vmixer “On” states.
Show Profile – Allows GPIO control and status of Show Profiles.
Input, Output, and Pin Numbers
The following tables show pin numbers as they would appear on a Telos Alliance xNode with 15-pin GPIO ports. Common pins that are not profile-specific are as follows and are not listed in the individual tables:
Pin 7 – GPO Common pin, typically tied to GND by application
Pin 8 – GPIO port GND
Pin 9 – 5vDC supply
Pin 10 – GPI common pin, typically tied to 5vDC by application
Line Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Computer Player Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Phone Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Codec Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Operator Microphone Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
CR Producer Microphone Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
CR Guest Microphone Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Studio Guest Microphone Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
External Microphone Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Studio Feed Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Control Room Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Record (Enable) Mode Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
External Timer Control Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
V-Mixer Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
Show Profile GPIO Table
Inputs (GPI)
Outputs (GPO)
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