Interoperability/ITSP

Internet Telephony Service Provider (ITSP) / Hosted VoIP solutions

There are sample configurations for various SIP telephony providers available:

Solution	Official Website
1&1
AOL Phone
blueSIP
Callcentric
Carpo
clara.net
dus.net
freenet iPhone
freeworlddialup
GMX NetPhone
Hong Kong Broadband Network
IP Austria
Nikotel
Placetel
PURtel/PepPhone
QSC IPfonie@basic
reventix SIPbase
sipcall.ch
SIPgate
T-Online
TeamFON
Telavox
voipbuster/sipdiscount.com
VoIPTalk
VoIPfone