Nortel has opened up its VoIP code to public inspection in an effort to encourage other companies to build compatible products and so increase the adoption of new multimedia services.

Comprehensive documentation has been promised to enable third-parties to develop and test their SIP-based clients and terminals with Nortel's Multimedia Communication Server (MCS) 5100 and 5200. As well as help create an open market where products work with another, Nortel is hoping opening up its code will push the MCS products in the middle of what it sees as the future of networks.

In March this year, it described the MCS 5100 as the biggest launch since Meridian 1 - its flagship traditional PBX phone product.

This "open-client strategy" will help vendors write or modify their own code to be compatible, using Nortel as a foundation, the company explained. Already signed up are Texas Instruments (chips), Uniden America (cordless phones), i3 Micro (residential IP gateways), and Polycom (voice/video conferencing). All will make their products compatible with the MCS - which sets up SIP sessions. TI will also write reference designs so their chip customers can make SIP devices such as phones and gateways that work with Nortel's MCS gear.

Nortel also announced it has verified interoperability between Nortel gear and Avici core routers. This is important to service providers that might want to use Nortel's edge routers in their networks because Nortel has designated Avici its partner to provide core routing. The verified interoperability includes Nortel's Multi-service Provider Edge switch routers as well as its Succession VoIP gear.

Nortel said such verification will continue as vendors update their platforms.