VoIP Companies

8X8 : Broadband phone, IP PBX, Video Phone
Aastra Telecom : IP Phone, PBX
Acme Packet :
Actena : VOIP Test and management
Aculab : Computer telephony development products /DSP
Adax : Offers a complete solutions evolving telecommunications networks
Advantage Century : VoIP phone , Gateway, USB phone
Alcatel : Gateway, Switch and more
Alepo : VoIP Billing and more
Alliance Systems : Media Servers, IP Gateways, Soft switch solution
Antasystems : Switch, IP PBX, IP Phone, Softphone
Antek : VOIP Gateway
Apex Voice : Billing, Messaging system
AudioCodes : Gateway, VoIP PCI, voice over packet (VoP) processors
Azatel : VoIP terminal adaptor, Gateway, WiFi, Switch
Brix Networks: VoIP Test system
BroadSoft : Hosted PBX, Moble PBX, IP Centrex
BroadVoice : Broadband phone service
Broadwing : VOIP Service
Brooktrout Technology :FAX over IP, Voice and Video Messaging etc
BT BroabandVoice : Phone service .
Centrepoint Technologies :(www.talkswitch.com) IP (PBX) phone system
Cisco System :
Citel Technologies ; IP PBX, IP Centrex
Clipcomm Inc. IP Phone, Adaptor, Gateway
Dialexia Communications : IP Based PBX system
Digium : Asterisk, IP PBX,  IP telephony interface devices for Linux
Daytek : VOIP Router
Draytel : SIP device to SIP device call and SIP device to PSTN calls.
Edgewater Networks : VOIP Products
Empirix  : VOIP Testing tools, solutions (Hammer..)
ExcelSwitching : VoIP Gateway, Signaling Gateway, Media server
EyeP Media : Softphone, web phone, IVR development tool kits (DIP/MGCP)
FreeIPCall : Phone service
GL Communications : VOIP Testing, analyzing, simulating  tools
GlobalCrossing : VOIP Carrier service provider, VoIP solution
Go2call : Phone calling service
Gossiptel : Voip service, Phone service
Grandstream Networks : IP Phone, Analog VOIP adaptor
Hughes Software Systems: VOIP Stack, development frameworks
i2Telecom : Phone service
i3 Micro technology : VoIP Gateway, Access device, Video Over IP
Innomedia : Gateway, Analog VoIP Adaptor, IP Phone
Intertex : SIP support NAT, access device, IP PBX
Ipeya : Hybrid IP- PSTN PBX phone system
Leadtek: VOIP Adaptor, Video Phone
Logitel : VOIP Gateway
Lucent Technologies:
MailVision : SIP Proxy server, SIP Mediation server, callback server
MediaRing : Carrier, Phone service
Mediatrix Telecom : VoIP Gateway, Access device
MetaSwitch : Class 5 SoftSwitch
Mitel Networks :  http://www.mitel.com
Multi-Tech Systems : Gateway, Gatekeeper (Switch)
myJabber : IP PBX, Softphone, IP phone
Net2Phone : Broadband phone, service provider
NetSapiens : SIP server, SIP conference server, IP PBX
Net.com : Gateway, Switch, IP telephony platform
NewCross Technologies: Gateway, Switch
Newport Networks : Carrier calls session controller
NexTone Communications : Session controlle
Nortel : http://www.nortel.com
Octtel Communications : Gateways
Pintel : SIP PBX, SIP Call Manager, Softphone
Polycom : IP Telephony
PowerDsine : Power over Ethernet
Pulverinnovations :  Mobile IP phone
Quintum Technologies : Gateway, Switch, VoIP solutions
RADCOM : Communication test systems
RADVISION : products and technologies for videoconferencing, video telephony, and the development of converged voice, video and data over IP and 3G networks.
RNKVoIP :customized wholesale plans for domestic and international VoIP services
Rodopi Software : VoIP Billing, Account Provisioning, Customer Care, RADIUS AAA CORBA Interface.
Sage Instruments : VoIP test system
Seawolf Technologies : SoftSwitch, IP phone, termination
Senao International : IP phone, Video phone
Sentito Networks :  Gateway, SIP Proxy server, VoIP solutions
SIPquest : VoIP server and application software, VoIP gateway , audio, video conferencing, SIP Proxy server, SIP-H323 convector
SIPURA Technology : VoIP Analog Telephony adaptor, Gateway, IP phone
SJ Labs : VoIP software Products
Snom Technology : IP phone, IP PBX, Softphone
Sonus Networks : Switch, SoftSwitch
Soyo Group : VOIP Phone , Gateway, VoIP Router , Prepaid calling service
Spirent Communications: VOIP test systems
Swyx:  IP PBX
SX Design : IP Phone, ATA technology for VOIP manufacturer, Development tool kits
Sylantro Systems : PBX, IP Centrex for Carrier
Sysmaster : Gateway, VOIP Billing, SoftSwitch, Gatekeeper, IP PBX, PDA Softphone
Telco Systems : Gateways
Telappliant : VoIP service, IP PBX, Telcentrex
TeleGea : VoIP Operating System
Telepacket : VoIP Phone service
Touchstone Technologies : VoIP test system
USA Datanet : VoIP phone service
VegaStream : Gateways
Veraz Networks : Gateway , Softswitch
Vocaltec : Gateway, VoIP Solutions
VoiceAge : Codec solution
Xten Networks : Softphone
Zyxel : VoIP Phone adaptor, Gateway