I stumbled across this old blog posthttp://biobug.org/index.php/2010/02/19/lotd-clean-your-cell-phone/
a while back, about serial communications with a motorola phone. This is some awesome functionality that I really want for a project I'm working on, so I picked up one of these C168i phones on ebay right away.
I can't get it to work, and I'm running out of ideas. I am hoping maybe someone here can help?
I first made up the cable using a 3/32 headphone jack, tested for shorts with a multimeter, looks great. I hooked it up to my Uno R3 using this information for pinout http://code.google.com/p/sserial2mobile/wiki/MotorolaC168i
and had no luck getting anything back from the phone, so I switched to a 5v FTDI cable and teraterm, 9600bps 8-n-1, no flow control. I had read elsewhere that the C168i uses on 3.3v TTL, so I ran the tx from the FTDI through a 5 ohm/10ohm voltage divider to get me to 3.3v, and left the FTDI rx connected straight to the FTDI, since 3.3V should still be a logic 1. Still nothing.
Anyone have any ideas? The phone has a keypad lock on it, but that first link did also. I can't find any information if motorola thought that was a security item and updated the software, but that's really the only idea I have. This isn't working at all, and it doesn't seem that complicated.
Thanks in advance.