An open source telephony switching and private branch exchange service. Allows peer-peer calling using a variety of voice over internet protocols.

VoIP provider for business and residential customers. No service charges.

VoIP provider offers full feature set with voice mail, caller ID, etc. Requires supplied broadband phone adapter.

Pre-paid VOIP services. H.323 IP phone, gateway, gatekeeper, NetMeeting or any other H.323 compliant terminal necessary.

A full featured VoIP/broadband phone to phone service primarily for calls within the US.

PC-to-Phone service for outbound calls only. Software download required.

VoIP service for phone-to-phone with adapter or peer-to-peer.

Offers monthly billing and pre-paid PC-to-Phone VoIP services. Also supports broadband telephone adapter for use without PC.

Provides Voice over IP and telecom service to international clients.

Prepaid system for PC-to-phone and web initiated phone-to-phone using VoIP.

Offers VoIP-based PC-to-Phone, Broadband Phone and Calling Card services.

Softswitch services such as routing, billing as well as VoIP call termination.

Wholesale voice over internet services.

PC to phone service based in Thailand. Software download required.

PC-Phone or device-to-phone United Kingdom based service.

A communications infrastructure provider includes IP systems, services, softswitches, and phones.

Voice over internet direct dial service without a PC. Owned by 8X8, Inc.

PC-phone internet voice service provider based in the United Kingdom.

Operates and builds international carrier networks using VoIP and TDM circuit transmission technologies.

PC to phone, phone to phone using device, voice over internet calls.