Connect your modem to the serial port of your PC.
Do your testing with Hyperterminal or similar program.
Start without autobaud mode, with DTE rate set to 19200.
Once you are able to comunicate at 19200 then try to enable
autobaud mode with the pulldown resistor and use a different
DTE rate with Hyperterminal.

Important!

Make sure you use RS-232 level translator (MAX232 type) between the RS-232 serial port of your PC and the TTL serial port of the Si2403.

Regards,

Luciano

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Terminal program:
(No setup, only one EXE file).

Terminal v1.9b 20040714.

Where to download:

http://bray.velenje.cx/avr/terminal/

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