I recently setup my Linksys SPA2102 without any problems. It was connected directly to the cable modem and then a router after the ATA.
As per the configuration instructions all went well and ATA registered right away with the FPL system. Incoming calls and audio was no problem.
Problen that I encountered was whenever I tried to dial out...the response was a fast busy tone and calls would never go anywhere and system would drop the line.
Upon research in the forum I was able to discover the problem which corrected the issue. Previous user had indicated that in the "Display Name" field of the Subscriber Information area I had inputted " Display Name " that had a character in it " & " basically wanting to display the first two names of the subscribers like " XXXXX & XXXXX ". Apparently using this character the system will not let this happen and generates the fast busy tone on making an outbound call. I removed the "&" character...and now outbound calls worked. It was as simple as that...but it took a while to find the solution!
So, what I am saying is that if anyone else runs into this issue be aware of that certain characters other than alphabet letters used in Display Name field cannot be used and will prohibit outbounds calls. I thought I would just bring this up again since it was mentioned sometime ago in ATA setup.
Hope this helps any other user encountering a similar problem