[time-nuts] My stubborn Z3801A

John Miles jmiles at pop.net
Sun Jun 13 20:21:06 EDT 2010


> Still to go:  The RS-232 signals look fine going into the cable,
> +/-5V, any
> ideas why the computer won't read it?  Am I missing something?  I
> tried two
> different ports in case I screwed one up one of the ports, but no luck.

Haven't been following the thread so someone may have suggested this before,
but: try another computer, a shorter cable, or perhaps a slower baud rate.
5 volts is near the bottom of the range for RS232 (the signalling levels are
supposed to be closer to +/- 15V, or at least +/- 12V).

Some RS-232 gear is happy with 5V but it isn't optimal in all cases.  The
problem you mention is more likely to be either a physical or protocol-level
mismatch than a real hardware fault.

-- john, KE5FX





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