Simple circuit to measure baud rate on a serial link

Hello -

I'd like to be able to measure the baud rate that a couple of sealed devices
are using to talk to each other over a serial (RS232) cable. I know that
they only use the common baud rates 9600, 19200, etc.

Can anybody give me some pointers on a circuit I could build that I could
daisy chain with the serial cable to do this? A digital readout would be
nice, but an analogue dial or set of LEDs would do. Or perhaps even a
circuit that generates an audio tone at a frequency that is some fraction of
the baud rate, and the tone could be compared to a set of reference tones
(or even tuning forks) by the user.

I'd like to build something cheap, compact and simple, rather than buying a
hardware or software protocol analyser.


.

Relevant Pages

  • Re: Simple circuit to measure baud rate on a serial link
    ... I'd like to be able to measure the baud rate that a couple of sealed devices ... and the tone could be compared to a set of reference tones ... Connect the tap off wires to the ...
    (sci.electronics.basics)
  • Re: Simple circuit to measure baud rate on a serial link
    ... I'd like to be able to measure the baud rate that a couple of sealed devices ... Can anybody give me some pointers on a circuit I could build that I could ... and the tone could be compared to a set of reference tones ...
    (sci.electronics.basics)
  • Re: Simple circuit to measure baud rate on a serial link
    ... I'd like to be able to measure the baud rate that a couple of sealed devices ... Can anybody give me some pointers on a circuit I could build that I could ... and the tone could be compared to a set of reference tones ...
    (sci.electronics.basics)
  • Re: Simple circuit to measure baud rate on a serial link
    ... I'd like to be able to measure the baud rate that a couple of sealed devices ... and the tone could be compared to a set of reference tones ... Well, you could use the serial data lines to clock a binary ... counter such as CD4040 and hang a few LEDs off the counter bits. ...
    (sci.electronics.basics)
  • Re: Simple circuit to measure baud rate on a serial link
    ... I'd like to be able to measure the baud rate that a couple of sealed devices ... Can anybody give me some pointers on a circuit I could build that I could ... but an analogue dial or set of LEDs would do. ... and the tone could be compared to a set of reference tones ...
    (sci.electronics.basics)