Trying to maintain what at one time had been an overwhelming majority market share in the rural switching market, Nortel this week is unveiling the first set of successful deployments of its SIP-enabled DMS-10 platform.

The evolution of the DMS-10, which was quietly unveiled at OPASTCO in July, begins with some software and the addition of a single-rack mounted Packet Gateway Interface along with an Ethernet switch, which will interface with the DMS 10's 3T98 system processor.

"We're really adapting the DMS-10 and adding a very inexpensive interface," said Dennis Couture, director of rural markets for Nortel. "On the one side, you've got IP and on the other it's the circuit-switched world."

The announcement this week brings with it several customers including McDonough Telephone in Colcheter, Ill.; Randolph Telephone in Asheboro, N.C.; and Golden West in Wall, S.D. Nortel said it has a total of 75 customers in the pipeline for this year.

Sometime in the first or second quarter of next year, Nortel plans to have an H.248 interface for the DMS 10 at which point the platform could be considered a full softswitch.

The company is intentionally taking a gradual approach to the evolution in part because of its position in the rural switching market. According Couture, Nortel still claims 66% of the market despite in-roads made by softswitch competitors like MetaSwitch and CopperCom. Playing to that installed base is a major factor in how the DMS is positioned, he said. The company's mutual distribution agreement with Calix also is a significant help in the rural market, he added.

"If you go immediately to a softswitch, all the line cards on your legacy switch have to be replaced," Couture said. "The migration path that we've mapped out is financially friendly to operators."