I don't think modems can detect single tones.  They can detect DTMF, but
only if they are the same tones (exactly) produced by a regular telephone.
You could use two tone detector chips each set to give you an output for
each tone.  Feed them into a PIC and RS232 the results to the PC.

Brian.

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Shawn Yates
> Sent: 12 January 2004 14:33
> To: PICLIST@MITVMA.MIT.EDU
> Subject: [OT]: Can Modem Detect Freq
>
>
> I need to use a computer to report to the central station of an alarm
> company.  To do this the modem must detect a 1400Hz tone followed by a
> 2300Hz tone.  Is this something a standard modem can do?
>
> Any input is appreciated.
>
> Shawn
>
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