---
title: "Using Physical GPI to Select the Primary Input Source of the Omnia Volt"
slug: "using-physical-gpi-to-select-the-primary-input-source-of-the-omnia-volt"
updated: 2024-12-17T12:50:48Z
published: 2024-12-17T12:50:48Z
canonical: "docs.telosalliance.com/using-physical-gpi-to-select-the-primary-input-source-of-the-omnia-volt"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.telosalliance.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Using Physical GPI to Select the Primary Input Source of the Omnia Volt

## Scope

This document covers how to use the rear panel GPI "Interface" connector to change the Primary Input Source.

> [!WARNING]
> Note: This also applies to the Omnia One.

## Description

Using external dry contact closures, you can use the rear panel "Interface" connector to change the Primary Input Source selection.

## Setup

Here is the GPI "Interface" connector pinout.

This is a DB9-F connector on the rear panel for remote control input, using contact closures or other logic-level systems.

Pin 1: +5VDC Out

Pin 2: Input Common +

Pin 3: Trigger input #1

Pin 4: Trigger input #2

Pin 5: Trigger input #3

Pin 7,8,9: GND

For operation, a voltage must be applied to voltage input on pin 2. The +5V power output on Pin 1 may be used as the input voltage. If this is done, the trigger inputs may be tied to 5V or left floating for a "high" state and tied to ground for a "low" state. In the below example Pins 1 & 2 are tied together.

Input Routing:

Trigger Inputs 1 & 2 select the primary input source. The secondary source must be set manually.

Input #1 acts independently to select either the analog input on a falling edge (grounding Pin 3) or the AES input on the rising edge (un-grounding Pin 3):

Input #2 acts to select the LiveWire input on a falling edge (grounding Pin 4). On a rising edge (un-grounding Pin 4) the state of Input #1 is examined to select one of the other inputs: ("L" = grounded, "H" = un-grounded)

xLxx = LiveWire input

LHxx = Analog input

HHxx = AES input

If Inputs 1 and 2 have simultaneous transitions, Input 2 takes precedence. So LLxx and HLxx switch to LiveWire.

Input #3 is the manual failover trigger:

xxLx = trigger a manual failover. This will cause the secondary input to be selected and the failback logic to be activated.

xxHx = manually clear a failover. This will cause the primary input to be selected and normal failover logic to be activated.

## Example

Here's an example where the main Input Source is Analog and the desired Secondary Source is AES.

1. On the "GPIO / Events" webpage, make sure that "GPO 3: Input Source Selection" is set to "Rear Panel GPI"".
2. Bridge pin 1 and 2 to activate the function.
3. Set your Input Source to Analog and your Secondary Source to AES manually via the menus.
4. Use GPI Pin 5 to switch between them. Normally, Pin 5 will be open so Analog will be selected. To select AES, ground Pin 5 and keep it grounded. Removing the ground will switch back to analog.

## Let us know how we can help

If you have further questions on this topic or have ideas about improving this document, please [contact us](https://www.telosalliance.com/support-request).