Nortel's so-called home location registers (HLR) decipher callers' account information, and if everything matches up, the voice call or data session goes through. Cingular is the fourth major U.S. carrier to switch almost entirely to 's HLR technology.
"We think this really solidifies our ownership of that market," Nortel spokesman Jay Barta said.
Nortel's equipment will eventually replace the hodgepodge of gear from different companies that Cingular now relies on. But the transition to a Nortel-only system could take several years.
Nortel's No. 1 competition in this market is Hewlett-Packard, which has claimed to have sold more HLRs than any other company. An HP representative had no immediate comment.
Nextel Communications, AT&T Wireless and T-Mobile have converted almost entirely to Nortel HLRs. Cingular hasn't.
"We're pushing now to try and change that," Barta said.