OT - Well, my guess, we just made 'em work, not the internals, but my guess is that you'd have to be in the system, every handset has a unique code, in the various company's databases, wrong hardware or NAM, you're ignored, CDMA doesn't use SIM cards, it's all in software, in the case of the handsets, hard coded for every device... Timing, as in T1 timing, is very accurately synchronized Nationwide via very expensive GPS receivers at every site, an interesting study of it's own, but as we power up, it goes to work to pop out the sync, near perfect, then over the next week or so. as it refines the accuracy, until it's happy... It's not there fro Date and time particularly, but no doubt it picks a universal code via that GPS...

Be better to look to WWV or GPS signals than hitch a ride... Even cellular has gaps, they do try to backfill, but I know a couple spots where it's still almost guaranteed it's going to go away... An atomic Casio wristwatch, tap into on of those!

I didn't know what a Arduino card is... http://arduino.cc/en/ - made me look... BUt maybe someone there has an idea...

weco