2-Wire System Integration Guide¶

This guide covers the integration and setup of analog two-wire party-line systems (e.g., ASL, Clear-Com, RTS, etc.) using the Green-GO Control software to configure your Green-GO interface.

Integrating such a system requires at least one Green-GO interface featuring a specialized Green-GO Engine, which links analog 2-wire intercom solutions to your Green-GO system.

Such an engine can connect one 2-wire channel (party-line, ring) and translate audio and call communication between both systems.

The integration challenges¶

Integrating an analog 2-wire party-line intercom system into your Green-GO system presents several challenges that need to be addressed to ensure seamless functionality.

As stated previously, a 2-wire integration requires a specialized 2-wire Green-GO Engine that allows you to match the impedance between the two systems and eliminate undesired echoes.

Mismatched impedance can lead to undesired signal reflections, poor audio quality, and increased signal leakage. With that said, keep in mind that things like a 2-wire's line impedance can vary based on factors such as the total length and type of cables used.

The 2-wire engine provides a manual function called Autonull that automates impedance matching and echo cancellation. However, the order of operation and adequate interface configuration are crucial for optimal results.

Additionally, 2-wire systems facilitating pin 2 (DC power supply) to implement a second duplex channel may require additional adaptation (e.g., Clear-Com TWC-701) or will only integrate with their second channel (B).

This is because a Green-GO 2-wire interface is only capable of integrating one 2-wire channel, which is expected to provide the audio signal on pin 3 of the 2-wire line.

Another challenge is the lack of a human operator who controls the signal flow between the two systems. Therefore, your configuration must ensure proper automatic signal routing between the systems.

Setup recommendations¶

With the main integration challanges defined, there are a few recommendation for your setup:

• Use ushielded network cable (U/UTP) to connect your Green-GO 2-wire interface to the Green-GO network to prevent any ground loops with the connected 2-wire system, leading to unwanted noise and audio artifacts.
• Ensure the maximum total XLR3 cable length connecting your Green-GO 2-wire interface is according to specifications and does not result in too low line impedance, as this can lead to signal degradation and increased noise.
• Properly terminate all 2-wire lines according to the system's documentation to maintain correct impedance and prevent signal reflections.
• Balance both systems using the Autonull function after both systems have been fully set up and tested. This is crucial for optimal performance as it balances system impedances and filters echoes.

Prepare your configuration¶

As with many other things, the configuration of your 2-wire integration will start with a user designated for your integration.

Therefore, the first thing you will need to do is to either to create or edit a user.

The 2-wire device profile¶

A device profile allows you to (pre-) define a device's configuration. The profile will load the configurations automatically once you assign the user to your interface (port).

The device profile required for this integration is the 2WR profile:

You can add the 2WR device profile to your user either during user creation or after the fact by using the in the user's navigation bar and selecting the 2WR device profile.

Configure the device profile¶

Once you have added the 2WR device profile, you can access it via a dedicated tab in the user's navigation bar.

The device profile features two cards for configuring the 2-wire engine: 2 Wire Port and Script Settings.

A successful 2-wire integration requires you to configure at least the following inside the 2 Wire Port card:

1. This option determines the general signal attenuation used by the Autonull function. You can manually set the signal attenuation or use existing presets if applicable.
2. This option determines whether the Autonull function is executed directly after completing a system boot.
3. Determines the call signal type used for the integration. Please check the documentation of your 2-wire system for the appropriate signal type to use.
4. Defines the minimum signal level before a signal is transmitted. This can be useful to blend out any 2-wire line noise.

It is important that you configure at least the Preset before you start the Autonull process. Additionally, providing appropriate configurations for things like Call mode and Gate threshold can help to complete your integration.

The signal routing¶

In order for communication between both systems to work, your user must have at least one of its 32 available channels assigned and configured.

A channel's configuration determines the audio signal flow between the two systems:

• Green-GO → 2-wire: Audio signals coming from the Green-GO network are controlled by a channel's Listen state and Level. Every assigned channel that is not muted () will be heard on your 2-wire system.
• 2-wire → Green-GO: Audio signals received by a Green-GO Engine require at least one channel to activate its Talk function. Each assigned channel with an active talk () will transmit the 2-wire communication to the Green-GO system.

Channel assignment¶

For a simple setup, one channel assigned to a group is sufficient for most two-wire integrations. This will effectively mirror the 2-wire party-line channel 1:1 in your Green-GO system.

However, more complex setups with multiple Green-GO channels assigned are possible.

Channel configuration¶

Since interfaces are usually not directly controlled by a human operator, you must ensure that your channel configuration allows for signals to be routed between both systems.

The simplest way to automate the Talk function is to configure at least one channel's Channel Mode to either Autotalk or Auto Reply.

You can edit a channel's configuration by selecting it and pressing the Edit button in the navigation bar.

While the channel mode Autotalk will always keep a channel's talk function enabled, Auto Reply acts as a remote enable or listen-in where the channel's talk function is enabled as long as the channel state is set to Active and another Green-GO user has enabled his Talk function for this channel.

Optional configurations¶

With completing the required channel- and device configurations, there is additional configuration that could enhance your integration further.

Control the call signal flow¶

In case of multiple channel assignments, configuring a channel's Call Mode can be benificial for managing the call signal flow:

• Green-GO → 2-wire: Enable the Receive option to transmit the Green-GO channel's call signals to the connected 2-wire system.
• 2-wire → Green-GO: Enable the Send option to transmit the 2-wire call signals to the Green-GO channel.

This allows you to control which channel assignments should receive and/or send call signals.

Enable special channels for your integration¶

The user's special channels allow you to easily implement things like the passive channel for program audio or important announcements.

Each of the special channels require a specific group that should be chosen carefully, as audio signals received via the special channels Announce and Emergency may influence or interrupt general channel communications.

Automatically load a custom script¶

Since Green-GO 2-wire interfaces don't feature any GPIO interface, external control can only be achieved by using a custom Green-GO script and implementing things like the OSC or script-to-script function calls.

The device profile allows you to define a custom script that will be automatically executed with each user load on a 2-wire Green-GO Engine.

Set up the integration¶

Once all preparations have been completed, it is time to adopt the interface and to set up the actual two-wire connection.

Adopt your Green-GO interface¶

First, ensure you have connected your Green-GO 2-wire interface to your network using an unshielded network cable (U/UTP). Using a shielded network cable should be avoided as there is potential for ground loops when connecting your 2-wire system with the interface.

Once connected to a PoE network switch, your interface should power up and appear automatically in the Connection view using the status Not adopted:

Here you can adopt the interface to your configuration by selecting your interface and pressing the button Adopt in the navigation bar:

This will bring up a pop-up that allows you to add the selected device(s) to your configuration.

Assing the user¶

To load your configuration, you must assign the user you have previously prepared to your Green-GO 2-wire interface port:

Once assigned, the interface will load the user configuration (channels, special channels, user settings, etc.), including the 2WR device profile.

Connect the systems¶

Before you continue leveling both systems by running the Autonull function, please ensure that you have checked the following recommendations:

• Ensure your 2-wire system is fully set up and tested, and all cable leads are properly terminated.
• It is essential to ensure that all microphones in your 2-wire system are muted to avoid background or feedback noise affecting the auto-nulling process.
• It is also a good idea to revisit previous recommendations to ensure a successful integration.

With these last checks completed, it is now time to connect both systems using a XLR3 cable.

Run the Autonull function¶

Once the 2-wire system is set up and connected to your interface, you must configure the connection by running the Autonull function. To do this, find and select your Green-GO 2-wire interface from the index tree and switch to the device's Audio tab in the navigation bar:

Here, you will find a 2 Wire Port card featuring a START button for the Autonull function. Pressing the button will start the auto-nulling process, sending a 1kHz tone to the connected 2-wire system to measure the reflected echoes and noise floor to optimize the signal separation.

After the Autonull function is complete, you may need to adjust and optimize the audio connection. This is best done by monitoring the VU-meter of the 2-Wire Port while listening for external communications on both systems and adjusting the properties From 2-Wire and To 2-Wire accordingly.

Multi-channel 2-wire systems¶

In systems that feature two duplex channels on a single cable (e.g., RTS, ), the integration will only work with Channel B by default. To integrate the first Channel A, you will need to use an adapter or interface.

Troubleshooting¶

Please check the troubleshooting guide for any common issues with 2-wire integrations.