I recently acquired a Motorola NEXTEL i670 from a friend's dad- it still has the original SIM card which is since no longer active. It still allows the phone to start up without that annoying "Insert SIM" popup that won't go away.
I recently discovered that the newer NEXTEL phones are shipped with a built in DirecTalk mode, which is basically an off-network (where NEXTEL service was unavailable or weak) Push to Talk walkie talkie mode.
It uses the 800mHz frequency, transmits digitally, and each phone has 10 built in channels and 15 codes per channel. You can also have a private conversation by entering a user's 10 digit phone number, but since these phones are deactivated and the phone number is actually editable in the menus, I'm going to try changing it to see if private talking functions with whatever number I use.
I'm expecting my grandfathers old work spare Nextel i335 in the mail tomorrow, so when I get it, I will try things out and post an update. I'm curious to see how this works out!
It'll be cool to have a walkie-talkie I can use, basically PTT service for free.
