has anyone successfully got one of these devices working with a SIP provider? I have tried every combination of logical settings in the SIP tab, and I can see a NAT translation to my SIP provider proxy, just keeps saying 'registering'.... :/
I have one working. Some of the fields do not make any sense. In the "SIP Domain" and "Outbound Address" enter the IP address of your provider. You can probably leave the "Proxy Address" blank. For some reason the phone uses the information entered in the "Phone Number" space as the authentication id, so enter your username in the "Phone Number" and "Authentication ID" spaces. Enter your "Authentication Password" as usual.
I must have tried 1000 combinations on this thing! It was the auth ID not being in the phone number and removal of the Proxy which fixed it. Seems odd to me as all other Linksys gear uses proxy as the referral to the SIP Gateway but I am getting used to inconsistency :/