So I've been working with the i355s that @BTPost sent and also some new ones that @Clyde sent me. One of the new radios is acting strange today although it was fine last night. This is a new i355 (Nextel) that has never had activated service. When I launch into Direct Talk and push the PTT, the phone says 'user not available' and then abruptly powers off. It can receive fine but powers off when attempting to transmit. Troubleshooting steps taken: New battery - same result Charger attached / unattached - same result Different SIM card from working radio - same result Reset all phone settings to factory with sec code 000000 - same result Change channel and code - same result Removed SIM - can't get to Direct Talk at all (No SIM message) Removed battery and SIM for 2 hours, powered on, reset, reboot - same results. Attached external moto PTT mic/speaker, pressed PTT on external device - same result. Banged phone on knee a few times - same result. I can't find a single Google hit on this problem and thought that maybe one of the i355 / iDEN gurus might have some advice. Very strange that it was working fine last night and even working on private channels via the line 1 code.