The Dynalink RTA 220 doesn't support ECN. The 
manufacturer complains that this is a hardware limitation not a firmware limitation. I think that they are lying, but hey. Either way, if you use RTA220 modem you'll have trouble talking to some places around the internet that use ECN. For instance, WaikatoUniversity's mail server sets ECN so you won't get any email from waikato.
Has anybody managed to half/full-bridge with these modems? -- TimCareySmith
One page links to RTA220:
