iQ Input Channel Says "Used EW"


This article applies to iQx and all QOR Engine based consoles. The concepts discussed here can also be applied to Element and Fusion as well. The specific example shown here is an iQ system.


Sometimes loading a source to an input channel on the console will result in the "Used EW" message appearing on the display for that channel. This article discusses the obvious and not so obvious reasons why you'd see this message. Before we discuss the reasons, let's discuss some Livewire basics: Advertisement and Subscription:

Livewire Stream Advertisement

A Livewire source will always advertise itself to the network. This allows you to see a list of sources in the browse window of a Livewire Destination prompt. It also allows your console's engine to determine if a device that is providing a source to the network is switched on or off. If the advertisement is not existing, the engine assumes that it is off and removes it from the list of available sources. Cool!

Livewire Stream Subscription

When a console engine loads a source onto an input channel, it is subscribing to the advertised stream. When a console engine subscribes to a stream, it changes the advertisement of the stream to indicate that it is loaded on a console. At this point, the stream advertisement is "owned" by the console engine. The advertisement of that stream can no longer be changed by any other device until the engine unsubscribes from the stream by unloading from the input channel.

1. Used Elsewhere

The most common reason for seeing the "Used EW" message is the obvious one: the source is in use elsewhere!

The engine is not able to change the advertisement of the stream to indicate that it owns it. It's because it's already owned by another console engine and is literally used elsewhere. The console engine can still present the source and its audio to the console's input channel, and will show "Used Ew."

Solution: Unload the source from the other console or change allocation settings

Unloading the source from the other console will free up the stream advertisement. Try loading the source on this console again.

If you plan to have a source available on more than one console, set the source to "shared" mode. See this technote here.

2. Firewall Software

This is the not-so-obvious one. If the source comes from a Windows IP Driver and is not used elsewhere, there's a good chance that Windows Firewall or similar is causing the issue here.

If Windows Firewall or otherwise is stopping the console engine from altering the advertisement as discussed above, the engine can't fully subscribe to the stream. The engine can't tell if it's because of this or if another engine already owns the stream. Therefore, it will display "Used Ew" on the input channel.

Solution: Turn off or configure your firewall settings

There are many intrusions prevention software packages out there. Microsoft Windows Firewall, Norton, McAfee, Kaspersky, Sophos, Symantec, and many others can block inbound / outbound network traffic to your computer and this can keep your software from “hearing” the multicast advertisement group on your Axia network. Our suggestion is to completely disable these, as a test, and then re-enable them with proper rules applied to allow this PC to communicate with the Axia network.

It's always a good idea to reboot the PC after making these changes.

Take a look at these technotes on the subject:

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