pic microcontroller discussion list <> wrote on Friday, October 10, 2003
7:50 PM:

> I want to use a stereo cable for a serial data transfer cable.
>
> 6' long, 1/8" jacks. (Radio Shack)
>
> Is there a convention (pin-out) for using stereo cables for serial
> data?

None that I am aware of, the important thing to remember with these jacks
is that as they are inserted or removed, the tip on the jack can make
contact with the sleeve and ring of the socket, and the ring can make
contact with the sleeve.

In other words, each wire can be briefly shorted to any other wire.  You
should note that when you are designing the comms hardware, even if both
devices are normally switched off when the cable is connected, you can be
sure that they won't _always_ be

It is possible to improve matters slightly by using the switch found in
most sockets to disable the line drive until some time after the jack is
inserted, but that is _far_ from foolproof- jacks being left half-inserted
or the use of extension leads will both foil that plan!

Best of all is to make the line drive cope with indefinite short circuits.

Nigel

--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk

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