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Running the network assessment test to see if you can get Cloud Voice

Before choosing BT Cloud Voice, we recommend you run a network assessment test to make sure you can get a high quality Cloud Voice service.

Once you’ve run the test, you’ll see voice quality measures for your network. You’ll need to pass the network assessment test to order Cloud Voice.

How to run a network assessment test

  1. First contact your Cloud Voice sales agent to get a test URL to use online
  2. Connect your computer to your router using an Ethernet cable
  3. Open the test URL in Firefox, Chrome, Safari or Edge
  4. Enter the number of calls you want to make or receive at one time.
  5. Download the network assessment to test your service.

 The network assessment test usually takes about three minutes. You’ll be able to work normally while the test runs – simply leave the page open and go back to it once the test has finished.

Troubleshooting for the network assessment test

To run the test, you’ll need to make sure your firewall has these ports open:

  • UDP 20000
  • 20001
  • 8090

If any of these ports are closed, your test will fail within seconds. Firewall and LAN guide

You’ll also need to make sure SIP ALG is disabled on your router. SIP ALG guide

Here’s what to do if you see this error message:
'Initialising is taking too long, please try again, and if you have further issues please report them to BT.'

  1. First, refresh the test and run it again.
  2. If the test still hasn’t worked, go to the Downloads folder of your computer and find the BCS.exe file. If you can't see one, you'll need to download the app again.
  3. Double-click the BCS.exe file, then hit Run on the screen that appears
  4. If you see a Visualware BCS Setup screen, simply follow the instructions on screen to set up the test. Or if you see a screen confirming BCS is already running, just click OK.
  5. Run the test again

If you’re still not able to run the test successfully, please contact your Cloud Voice sales agent.

Voice quality measures for the network assessment test

Running the network assessment test will give you voice quality measures that your network must pass for you to use Cloud Voice successfully.


May result in echo or voice distortion, and can impact the overall voice quality.


Can severely impact voice call quality by making calls break up and sound choppy.

RTT (Round Trip Time)

High RTT can cause gaps in the conversation.

MOS (Mean Opinion Score)

A standard measure for voice quality, estimated from the Jitter, Loss and RTT results.

Bandwidth (the speed of the broadband service)

The amount of usable bandwidth that would support Cloud Voice. This will always be lower than any total bandwidth test.

If you don’t pass these voice quality measures, here are improvements you can try:

  • Stop any major downloads or programs while running the test
  • Make sure all cables and ports are connected and installed properly
  • Only use an Ethernet connection – you cannot run the test on a wireless connection
  • Restart your routers and hardware – this can resolve many technical faults or bugs
  • Make sure all software is up to date
  • Use QoS settings to prioritise voice on your network traffic
  • Replace outdated or faulty hardware

If you continue to fail the network assessment test due to voice quality measures or bandwidth, please contact your service provider so they can resolve them.

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