🚀 go-pugleaf

In article <C1Ewyx.2ny@dcs.ed.ac.uk> gst@dcs.ed.ac.uk writes:

>Further to my previous posting concerning my record of faulty serial ports, I
> now
>have my machine back and working.
>
>The engineer at Norwhich Computer Services reports
>that the serial driver chip had suffered static damage (the driver chip is a
> CMOS
>device which uses a charge pump to create the +/- RS232 voltages).
>He suggests extreme care be taken with the port and that screened (hence
> earthing
>from one machine's chasis to another) leads and plugs should always be used.
>I would have thought that given the typical nature of serial port use (noisy
>environments etc) that CMOS drivers are a bad idea, I intend to make up my own
>buffer to protect my port. I have never heard of this problem occuring on
>other euqipment using serial ports.
Generally on serial hardware you're not supposed to connect PG (pin 1 on
25-way) to the PG on the other end (or so I was told). As the 9-pin has
no PG, I don't know what you really should do.

A3000 serial ports never seem to blow when they've been working before... 
however, I know of *many* people who have got the chips and had them D.O.A.

The old A5000's use the same method (ie charge pumps), as does our serial
card (socketed AD238's). I note with interest that the A3010/4000 use the
(very) tried and tested 1488/1489 combination with unregulated +/-12v
supply (nice you you've got it). Bombproof, practically, the way it used
to be done in 'the good old days'.

Hugo
-- 
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                                     "Did I say that? My lips didn't move..."
Hugo Fiennes - The Serial Port                      altman@cryton.demon.co.uk
                                                or altman@cix.compulink.co.uk
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