By testing your broadband speed you can report back to us on your estimated speeds. With this information we can understand how many handsets you would be able to run on your broadband without suffering quality issues.
Here are a few below:
http://www.broadbandspeedchecker.co.uk
http://www.broadband-finder.co.uk
http://www.speedtest.net/
http://www.thinkbroadband.com/speedtest.html