CheapCalling.com

Fortified Provider Network
[USA] A national network which contracts with insurers and third party administrators. Site describes the company and offers provider look-up, FAQs, and employment opportunities.
www.fortifiedprovider.com/

Texas Instruments VoIP Solutions
B2B manufacturer of VoIP equipment including IP Phones, VoIP Gateways, High Density Gateways, voice-enabled Cable & DSL Modems.
focus.ti.com/

My VoIP Store
Australian-based (Brisbane) VoIP consultant and B2C e-commerce site for VoIP hardware.
www.myvoipstore.com.au/

Provider Select, Inc.
[USA] Offers several services to insurers, including preferred provider network, workers' compensation network, large claim negotiations, utilization review services, and case management.
www.psippo.com/

Gnome-o-Phone
Graphical VoIP software for the Linux Gnome desktop. Includes RtpTunnel utility for tunneling RTP UDP-based traffic through a firewall.
gphone.sourceforge.net/

Linphone
SIP based web phone. Supported audio codecs are G711, LPC10-15, GSM, and SPEEX.
www.linphone.org/

Asterisk
Open Source telephony switching and private branch exchange (PBX) daemon. Supported signalling protocols: H.323, SIP, MGCP, SCCP (Cisco Skinny).
www.asterisk.org/

GNU Bayonne
A free, scalable telecommunications application server by the GNU Project.
www.gnu.org/

NAT H323 under Linux
Mini-HOWTO for NAT & H.323 - configuring Linux to support H.323 while using network address translation.
pierre.clerissi.free.fr/

isdn2h323
Project homepage for isdn2h323, a Linux-based ISDN to H.323 gateway.
www.telos.de/