Have a SPA900 connected to a SPA400 with a single analogue line plugged into Port 1 of the SPA400.
If we make a call through the SPA400 the person called hears a very choppy call like a very bad SIP call.
Found the support document on choppy SPA400 calls and carried out all recomendations in the document with relation to codec and VAD but the problem still persists. http://www.cisco.com/en/US/products/ps10030/products_qanda_item09186a0080a35a1f.shtml
All devices are on latest firmware and we have been making calls for years using SIP (L1) and Mediatrix ISDN (L3) with no problem. But using the analogue line through the SPA400 (L2) is now a problem.
Rebooting the SPA400 usually fixes the audio quality for the next call but subsequently the line goes crap again.