This is maybe a bit off-topic, but you may find easier implementing this as purely software/firmware thing for simtrace itself rather than building a separate device :)

Cheers!
Lukas

On Thu, Jun 28, 2012 at 1:31 PM, Kevin Redon <kevredon@mail.tsaitgaist.info> wrote:
Hi,

Excerpts from Gabriele.rago's message of Thu Jun 28 12:38:52 +0200 2012:
> Hello all, I would do a sim-emulator software that runs on my PC.
>
> First thing to do is a an interface to connect my PC with sim slot phone.
>
> So I am using this simple interface :
>
>
> I took a CP2102 module, see this page for example
> http://esaid.free.fr/Cdotnet/USB_serial.htm,
>
> then I have put a diode between TXD and RXD, then I have connected RXD to
> I/O of phone sim slot,
>
> DSR of CP2102 module to RESET of phone sim slot and connected the two
> grounds.
>
>
SIM cards come in different classes (different operating voltages). First check if this is matching.
One important point is that you are completely ignoring the CLK pin.
Thus you baudrate might not match the one set by the phone, and additionally you can also be out of sync with the clock.
Some old phone have a fixed standard baudrate, that might help (use an osci to debug).

kevin