Inexbee - Mercuro IMS Client. SIP/3GPP/IMS and RCS compliant softphone.

Freespeech - Freespeech provide a flexible low cost SIP VoIP service for the home and small business user.

I.D. Rank Security; Inc - myKryptofon is a SIP; STU III-like (Secured Telecommunications Unit) phone that secures your voice calls; conference calls; chat; and file transfers with AES 256-bit encryption using symmetric keys.

Wuchuan Network(shenzhen)Limited - A newly developed hi-tech SIP phone for enterprise supporting 5 SIP servers synchronously; (POE) function and 128*64 LCD display.Besides; it supports 3 interactive soft key to play humanized operating

Messagenet - Carrier-grade SIP VoIP service provider based in Italy with DIDs availeble in many European countries.

Interactive Intelligence - Interaction Media Server (SIP based).  It can scale from 200 users to 5000. Does call recording; compression; transcoding; transcrypting (SRTP support); plays wav files; N*M config and much more.

Telnowedge - Web/ruby based provisioning system for Asterisk based and SIP compliant IP phones

Cinetix Telecom Solutions - Cinetix MQT uses a distributed End-to-End traffic generation to test the Quality of Service across a telecom network. MQT SIP based active probes perform calls used to produce a rich set of KPI/KQI.