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Text File
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1993-12-25
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3KB
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81 lines
What is it?
~~~~~~~~~~~
An Impression document which contains details on how to construct an
opto-isolator for your serial port.
Non Impression owners:
A text version of the Impression document is also included. Inside the
Impression document you can find the draw files which contain the circuit
diagram and stripboard layout.
Why use it?
~~~~~~~~~~~
The opto-isolator avoids problems with static build up which can damage your
serial port. (The A5000 serial port is *very* sensitive to this - a design faultI believe.)
The opto-isolator will also protect against a voltage difference between
computers. One of my friends PC's was using a two pin power lead, the RF
suppression network present in its PSU was leaking 100V at about 1mA, this
could easily damage a normal serial port!
If the opto-isolator circuit is built with the correct materials (a PCB is
recommended for this) it could be used to isolate from 'live' circuits. The
opto-isolator chips are rated at 1KV. Do NOT attempt this unless you know what
you are doing.
What do I need to build it?
~~~~~~~~~~~~~~~~~~~~~~~~~~~
You will need a soldering iron, wire cutters, a drill bit or track cutter is
also needed. You will need to be familiar with building small circuits on
stripboard and will obviously need the components in the circuit.
You do not need any test equipment though a voltmeter will aid testing and
fault finding.
How do I connect it to my computer?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The opto-isolator will fit in line with your normal RS232 connection lead. It
requires a +5V power supply, this can be obtained from a spare floppy / hard
disk power connector. A locking phono socket is a useful way of making +5V
available from your computer without having trailing wires.
How much will it cost?
~~~~~~~~~~~~~~~~~~~~~~
This depends on where you get the components from, I built it for about 35
pounds.
Disclaimer
~~~~~~~~~~
I can accept no responsibility for the use/misuse of this circuit or any damage
arising to equipment/persons.
However the information provided in this distribution is believed to be correct,if you should spot any errors please contact me.
Copyright
~~~~~~~~~
There is no copyright on any part of this distribution. It is public domain.
How to contact the author
~~~~~~~~~~~~~~~~~~~~~~~~~
If you have any problems, questions, suggestions, praises, criticisms etc pleasedo not hesitate to contact me.
You can email me during term time
Internet: gst@dcs.ed.ac.uk
or you can write to me at
George Taylor
16 Newton Crescent
Dunblane
Perthshire
FK15 ODZ
You will receive a much quicker response if you email me.