A listing with some useful VoIP, Video Conference, and Instant Messaging resources.
- VoIP VC IM Protocols
- Compression Codecs
- Standard Specifications
- Online Tutorials
- Books
- Network Tools
- SIP Servers
- RTP Relay
- STUN and TURN Servers
- H.323 Servers
- Media Servers
- Multi Conference Units
- Selective Forwarding Units
- IP PBX Software
- IP PBX GUI Web Interfaces
- RTP Relay
- Softphones
- Command Line Tools
- Command Line Phones
- Hardphone Brands
- Video Conference Terminals
- IP PBX Hardware Brands
- VoIP Libraries
- VoIP Forums and Sites
- RTC Events
- Dundi
- Voip routing protocol
- UDP port 4520
- H.323
- Voip signalling protocol
- IAX2
- UDP port 4569
- Jingle
- MeGaCo
- Voip signalling protocol
- MGCP
- Voip signalling protocol
- MSRP
- RTP
- RTCP
- SCCP
- SDP
- SIP
- Voip signalling protocol
- UDP port 5060
- TCP port 5060 (optional)
- TCP port 5061 (optional secure TLS)
- SIP/SIMPLE
- SRTP
- STUN
- TURN
- XCAP
- XMPP/Jabber
- TCP port 5222 (client connection)
- SRV resource record example: _xmpp-client._tcp.example.net. 86400 IN SRV 5 0 5222 xmpp.example.net.
- TCP port 5223 (optional secure TLS connection)
- TCP port 5269 (server connection)
- SRV resource record example: _xmpp-server._tcp.example.net. 86400 IN SRV 5 0 5269 xmpp.example.net.
- ZRTP
- ADPCM
- AMR
- NB Narrow Band
- WB Wide Band
- G.711 a-law (PCMA)
- IDSN codec
- Used in Europe
- G.711 u-law (PCMU)
- IDSN codec
- Used in North America
- G.719
- G.722
- HD
- G.722.1 Siren7
- G.722.1C Siren14
- G.722.2
- G.723.1
- G.726
- G.726 AAL2
- G.729A
- GSM
- iLBC
- LPC-10
- Silk
- SpeeX
- 4-48 kbps
- Signed Linear PCM
- Ogg Vorbis
- Opus
- WAV (SLIN)
- WAV (GSM)
- H.263
- H.263p
- H.264
- MPEG-4 AVC
- H.265
- MPEG-H Part-2
- VP8
- VP9
- RFC3261 : SIP: Session Initiation Protocol
- RFC3262 : Reliability of Provisional Responses in the Session Initiation Protocol (SIP)
- RFC3263 : Session Initiation Protocol (SIP): Locating SIP Servers
- RFC3265 : Session Initiation Protocol (SIP)-Specific Event Notification
- RFC4566 : SDP: Session Description Protocol (obsoleted)
- RFC3264 : An Offer/Answer Model with the Session Description Protocol (SDP)
- RFC3508 : H.323 Uniform Resource Locator (URL) Scheme Registration
- RFC4123 : Session Initiation Protocol (SIP)-H.323 Interworking Requirements
- RFC6120
- RFC6386 : VP8 Data Format and Decoding Guide
- ColumbiaEdu - SIP Tutorial
- CornellEdu - Understanding SIP
- JDRosen.net - Tutorials
- RFC3261 Simplified
- SIP Introduction
- SIPTutorial.net - SIP
- TutorialsPoint - SIP
- VoIPMechanic - SIP Basics
- VoIP Protocols: Introducing SIP
- Terena - SIP Tutorial
- Oracle - SIP Tutorial
- Startrinity - SIP Articles
- Wisdomjobs - SIP Tutorial
- MIT - SIP Basics
- Leonid - SIP Tutorial
- Aarnet - SIP Tutorial
- Independentsoft - SIP Tutorial
- SIP: Understanding the Session Initiation Protocol
- SIP Beyond VoIP
- Internet Communications Using SIP
- SIP Demystified
- {Brekeke Sip Server](https://www.brekeke.com/)
- Kamailio
- Linphone Flexsip Server
- OfficeSIP
- Opensips
- ReSIProcate
- sipXcom
- SipWise C5
- Kaplansoft TekSIKP
- Mobicents
- MyVoipipp MiniSIPServer
- YXA (Legacy | Linux | SIP)
- RTP Proxy
- RTP Engine
- Media Proxy
- Doubango Telepresence (Linux | SIP)
- Freeswitch MCU (Linux | SIP)
- i2conf (Legacy | Windows | SIP)
- Medooze MCU (Linux | SIP)
- Marakew MCU Server (Linux | SIP)
- OfficeSIP (Winodws, Linux | SIP)
- Openmcu-ru (Windows, Linux | SIP, H.323)
- Asterisk FSU (Linux | SIP, H.323)
- Janus
- Jitsi Video Bridge (Linux | XMPP)
- 3CX
- Askozia (Windows, Linux | SIP, H.323, MGCP, IAX2, SCCP, XMPP)
- Asterisk
- Communigate
- FreeSwitch
- FusionPBX
- Bicom Systems
- Elastix
- Enswitch
- Mizutech](https://www.mizu-voip.com/Software/VoIPServer/WindowsPBX.aspx)
- Kazoo
- OfficeSIP (Windows, Linux | SIP)
- PCBest Networks SIP PBX
- Pascom MobyDick
- Thirdlane
- Yate (Windows, Linux | SIP, H.323, MGCP, IAX2, XMPP)
- Yeastar
- FreePBX
- Asterisk GUI
- 3CX Phone (Windows | SIP)
- Blink (Windows, MacOS, Linux | SIP, MSRP, XCAP)
- Cornfed Sip User Agent
- Counterpath Bria and Bria Teams (Winodws, Android | SIP, XMPP)
- SIP IP Communicator (Windows | SCCP)
- CSIPSimple (Android | SIP)
- Draytek Soft Phone
- Ekiga (Windows, Linux | SIP, H.323)
- GNOME Empathy (Linux | SIP)
- Grandstream Wave (iOS, ANdroid | SIP)
- Jitsi (Windows, Linux | SIP, XMPP)
- Kaplansoft TekPhone (Windows | SIP)
- Linphone (Windows, Linux | SIP)
- Microsip (Windows | SIP)
- Mizutech (Windows | SIP)
- OfficeSIP (Windows | SIP)
- Polycom RealPresence Desktop (Windows | SIP, H.323)
- Polycom Telepresence m100 (Legacy | Windows | SIP, H.323)
- Polycom PVX (Legacy | Windows | SIP, H.323)
- SipDroid (Android | SIP)
- SNOM 360 (Windows | SIP)
- Telephone (MacOS | SIP)
- tSipClent
- Twinkle (Linux | SIP)
- [Twinkle]((https://mfnboer.home.xs4all.nl/twinkle/) (legacy | Windows | SIP)
- wxCommunicator (Winodws | SIP)
- Yate Client (Windows | SIP, H.323, IAX2, XMPP)
- Yealink Desktop VC (Windows | SIP, H.323)
- Zoiper3 (Legacy | Windows | SIP, IAX2, XMPP)
- Zoiper5 (Windows, Android | SIP, IAX2, XMPP)
- sipp
- sipsak
- Cornfed SIP User Agent
- [Linphonec] (Windows, Linux | SIP)
- [Pjsip pjsua] (Windows, Linux | SIP)
- Kaplansoft SIPCLI (Windows | SIP)
- openRTSP (Linux | RTSP)
- sipcmd (Linux | SIP, H.323)
- [sipcmd2](https://github.com/guisousanunes/sipcmd2 ( (Linux | SIP, H.323)
- sipsimpleclient (Linux | SIP)
- Twinkle (Linux | SIP)
- [Twinkle]((https://mfnboer.home.xs4all.nl/twinkle/) (legacy | Windows | SIP)
- Avaya
- Cisco/Linksys
- Digium
- Elmeg
- Fanvil
- Gigaset/Siemens
- Grandstream
- HTEK
- Huawei
- Innovaphone
- Mitel/Aastra
- Obihai
- Panasonic
- Polycom
- Stentofon
- Snom
- Tiptel
- Ubiquiti
- Yealink
- Avercomm
- Cisco/Tandberg
- DCM
- Grandstream
- Huawei
- LifeSize
- Logitech
- Polycom
- Vaddio
- Yealink
- ZTE
- Atcomm
- Avaya (SIP, H.323)
- Cisco (SIP, H.323)
- Digium (SIP, H.323)
- Gigaset/Siemens (SIP)
- Grandstream (SIP, H.323)
- Yeastar
- Abto (SIP)
- PJSIP (SIP)
- BareSIP (SIP)
- eXoSIP (SIP)
- JAIN-SIP (SIP)
- JsSIP (SIP)
- Linphone Liblinphone SDK (SIP)
- MjSIP (SIP)
- oSIP (SIP)
- Ozeki (SIP)
- PjSIP (SIP)
- ReSIProcate (SIP)
- SIPML5 (SIP)
- SofiaSIP (SIP)