FWIW... Version 6.2 of Cisco's sip code for the 7940/7960 was posted on Cisco's download site Feb 17th. The v6.2 release notes suggest the following caveats were addressed: SIPPhone: CANCEL messages not formatted properly after 180 received Branch ID is not compliant to RFC3261 SIP IP Phone resets rtp session when it receives sip re-invite Open v6.2 caveats include: SIPPhone: DND config causes weird NTP behavior Media takes 0.4 sec to be set up The v6.1 coded reportedly addressed 18 caveats from v6.0 code.