Cisco and Avaya have been battling over market share in the enterprise unified communication, VoIP and TDM equipment market, according to the market research firm Infonetics Research. The two have been neck-and-neck in the market for more than two years, and they both remain at the top despite lower revenue this quarter. Meanwhile, NEC and Siemens Enterprise are among the few vendors who have managed to increase their PBX revenue this quarter.

“We have been closely monitoring year-over-year growth rates for signs of a strengthening PBX market recovery, and the fact that global revenue in the first quarter of 2012 was down slightly (-.6%) from the year-ago first quarter indicates that we are looking at another year of modest growth in the PBX market,” noted Diane Myers, principal analyst for VoIP and IMS at Infonetics Research, in the report.

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Myers added that the enterprise telephony market has become very aggressive, mostly due to businesses adding fewer employees or holding off on upgrades for as long as possible.

The global PBX/KTS system market declined 4.6% to $2.06 billion in 1Q12 from the previous quarter, but the year-over-year sales of pure IP PBX systems are up almost 4% and unified communications sales are up 16%.

The report also included some regional perspectives, noting that the Asia Pacific region had the strongest quarter-over-quarter results, up 16% in 1Q12 from 4Q11.  Infonetics remained cautious about North America and the EMEA region because of the current economic situation and future uncertainty within specific countries in Europe.

The Caribbean and Latin America region was a bright spot during the first quarter, up 18% from the first quarter of last year for combined TDM, hybrid IP and pure IP PBX revenue due to healthy growth and new business creation across the region.