Three are the only company that will let you return or cancel contracts if you have no signal at home, If I Remember Correctly!
I can only find the details about the three dongles on their site after a quick look.
http://ask3.three.co.uk/srvs/cgi-bin/webisapi.dll/,/?new,kb=mbb,ts=mbb,t=casedoc.tem,case=obj(689),varset_username=MBB:mbbUser
I and my family all have three phones, and we had a problem a couple of weeks ago with no signal at home, one phone call later and they had apologised for the problem, told us it was going to take perhaps two weeks to sort it out and that they would halve our monthly bills for the month for the inconvenience.