IP TELEPHONY （お仕事用のリンク集）
SIP CENTER.COM
SIP FORUM
SIP (Columbia Univ.)
iptel.org
SIP Product List
SIP (IETF)
Listing of Public SIP Servers
SIP Interoperability
情報化研究会
代理店どっとこむ
VoIP推進委員会
谷島宜之の情識
VOIDA.ORG
asterisk.org
Linux Telephony
IT Papers.com
Communications Solutions
CommWeb
Customer Inter@ction Solutions
Internet Telephony
mySIP.ch
TOTAL TELECOM
The VON Coalition
CONTACTCENTERWORLD.COM
ITU (International Telecommunication Union)
3G Newsroom.com
Business Communication Review: White Papers