Alcatel, Westell, Mitel and Siemens are the first vendors to submit their hardware for the Telecoms Industry Association's (TIA's) second phase of IP PBX testing.
They will see their IP telephony products tested for interoperability with older time-division multiplexing systems using Digital Private Networking Signalling System (DPNSS). Westell also will be submitting its IP gateway products for testing.
"Phase one involved getting as many of the manufacturers together as we could," said Alan Cobb, director general at the TIA.
"Phase two will involve testing vendors' products in a serial manner; we don't need to have all the products together at the same time. It is possible that more manufacturers will come on board at a later stage."
Cobb added that the decision to test DPNSS compatibility, rather than the alternative QSIG standard, has limited the number of vendors signing up to the second phase of testing.
Daniel Bausor, head of communications for UK and Eire at Avaya, said his firm completely supported both interoperability and the TIA's efforts.
Avaya was one of four vendors to sign up for the first round of testing last year. The other three were Alcatel, Cisco and Nortel.
"We invest a lot in interoperability testing," Bausor said. "Avaya Labs has a facility in Denver specifically for this, and there's also a lab in Guildford for testing on localised systems."
Bausor added that Avaya has tested and uses Westell's DPNSS and QSIG converter. He said it had gained a lot from the first phase of testing, addressing IP interoperability.
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