Re: help on pc-phone interface

Hi,

then I have put a diode between TXD and RXD, then I have connected RXD to I/O of phone sim slot,

I'm not sure a diode would help here at all ... Usual solution is to have an open collector output with a pullup. Then you have all the issue where a phone could request change of speed via the special PPS procedure (IIRC) and I'm not sure you'd be able todetect and follow it. Adapting the fw of a simtrace board seems like a better solution. Cheers, Sylvain