Is there such a list? GV of no interest. pay providers offering free SIP plan?
which features on Obi* device supported
which SIP provider features supported
SIP TCP
SIP TCP TLS
mwi
codecs
non-5060 ports
audio proxying vs stun/turn
documented tweaks/hacks needed in certain situations
callcentric
sip2sip
antisip
fonosip
