IP-Centrex Systems : Lucent Technologies

Lucent Technologies is the second-largest supplier of Centrex systems, based on its 5ESS digital central office, which has been installed in a number of countries. Lucent made an early start in 2000 with its iCentrex product, which is based on the iMerge gateway, extending Centrex over IP and wireless networks. The iCentrex solution is actually switch independent and could work with other vendors' central offices. This product allows for the use of a mobile phone with Centrex dialing and other features when the user is in the Centrex service area. Sharing one voice mailbox between wireless and wireline Centrex services is also possible, with more than 1,000 wireless handsets feasible in one building.

Lucent claims that its 5ESS switch has the least downtime of any CO system in the U.S. public networks. The iCentrex development relies on the 7R/E Packet Driver software to deliver full PBX-like parity, including call transfer to voice mail and auto attendant. The wireless Centrex features work with either code-division multiple access (CDMA) or time-division multiple access (TDMA) technologies.

The iMerge Centrex Feature Gateway (CFG) enables users to enjoy worldwide Centrex service, as emphasized in Figure 3.


Figure 3.3: Worldwide IP-Centrex.
Lucent identifies the benefits of worldwide IP-Centrex as including a single dialing plan and uniform telephone system at all locations, including mobile and at-home workers, as well as branch plants or offices. IMerge enables a customer to be freed from service area boundaries with the delivery of existing Centrex and new services across a packet network.

Based on the encouraging results from field trials of Lucent's iMerge product SBC Communications launched commercial IP-Centrex service in September 2002, starting with availability in five major cities across the United States. SBC claimed that it was the first major carrier to bring these new IP-Centrex capabilities to the market.