Dial Problem with External SIP provider using IP 706
I picked up an AdTran IP 706 to use as a SIP phone for travel. I have a SIP service and have been using linksys/Cisco ATA's so I know the service is working.
I am having difficulty with documentation on the IP 706. After some slow plodding, I have managed to get the phone connected and logged into the SIP service.
Phone is the Adtran IP 706 updated to the latest firmware version 2.4.1/2.1.0. I am not using a host switch but an independent SIP service provider.
Calls through the SIP service to the IP 706 work fine, the phone operates well for these incoming calls with all functions working properly. The issue is that I can not dial out calls with the IP 706. I get a dial tone but after I enter the 10 digit number (we have to include area codes), I get a fast busy. I am unsure if this is a ghost fast busy from the IP 706 or if the fast busy is coming from the SIP service. I also do not know how to alter the dial string, or if the dial string is the problem with why the service is not accepting the outgoing call request. [I am loading the configuration from an individualized adtran_000000000000.txt file which is loading from the tftp server and configuring the phone.] I have tried the default DialPlanExternal as provided by Adtran as well as a similar configuration recommended by the SIP service for Linksys/cisco (same format except linksys uses enclosing round bracket.). I am guessing this is not a dial string issue but rather is related to leading or tailing data that is used in initiating the call.
The service recommends G.729a for the codec. I am assuming from the incoming call functioning that the issue is not in codec negotiation.
Any suggestions on the cause of the problem & how to get the outgoing dial operation working?