Recently, Sprint has launched the first of its much-anticipated Sprint/Nextel combo phones, the Motorola ic502. The ic502 uses Sprint's CDMA 1xRTT network for voice calls and data connections, but Nextel's iDen network for walkie-talkie service.Sprint has wanted to move customers off of Nextel's unusual network for a while, but has moved gingerly for fear of enraging Nextel's extremely loyal business customers. Not only does Sprint have to run two redundant networks right now, the FCC has commanded Nextel to leave the 800 Mhz band it has been entrenched in because of interference complaints from public safety agencies using nearby frequencies.The problem is that no other technology mimics iDen's instantaneous push-to-talk capability. Searching for a good PTT solution has led Sprint to accelerate the rollout of EV-DO Rev A, a high-speed, low-latency data technology that could carry a Nextel-quality walkie-talkie system.Meanwhile, Sprint hasn't been adding many new towers to Nextel's network, causing trouble with blocked and dropped calls.