DALLAS-AT&T Wireless Services has launched its commercial rollout of Interim Standard-136 service with a Dallas in-office system, using L.M. Ericsson microcells and Nokia Corp. handsets.
The office system installed at Perot Systems uses a distributed antenna strategy, and allows handoffs to the public cellular network. The same IS-136 cellular phone can be used on the public and in-office network.
AT&T said it expects to upgrade most of its wireless systems to IS-136 in 1996. The wireless operator uses Time Division Multiple Access IS-54 technology in most of its 800 markets nationwide. IS-136 is an advanced TDMA technology.
AT&T said it also will test the IS-136 equipment being sold by AT&T Network Systems. The reorganization of AT&T Corp. announced in late September pulled AT&T’s cellular and paging division away from the company’s wireless equipment business. AT&T hopes to allow each division to follow the path of greatest opportunity. AT&T Wireless and AT&T Network Systems are scheduled to become independent, publicly traded companies, possibly by year-end 1996.
One feature of IS-136 is sleep mode, during which time the phone sleeps (except for six milli-seconds of each second cycle) until awakened by an incoming call. Standby battery life is at least doubled, AT&T said.
The phone also can receive short alpha-numeric messages. If a call-back number is included in the message, the recipient can dial it by pressing a soft key, AT&T said.
IS-136 service also allows location identification, meaning the network can determine whether the user is on the office system or the public, macro system. If the word “office” appears on the phone display, the user knows the call will be billed at the monthly office rate. Otherwise, the phone will operate as a traditional cellular phone.
The Perot network includes two microcells with custom-designed antenna distribution. The network is connected to the Perot PBX, and the employee’s desk phone and cellular phone will both ring.
