I came across a way to connect a keypad to micro with only one pin;
It appears in "Electronic Design Online". This is the web version
of the trade magazine - worth a read and best of all it's free !

http://www.penton.com/ed/Pages/magpages/may0198/ifd/0501ifd.htm#5

Regards...

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Dave Duffy         Audio Visual Devices           AVD@uq.net.au
Unit 8, 9-11 Trade Street, Cleveland, Queensland 4163 Australia
Phone: +61 7 38210362                 Facsimile: +61 7 38210281
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