Pentax Cable Switch F for the ZX-5n and other cameras.

I just purchased a Pentax Cable Switch F.  I knew it was a simple device.  So
I got my voltmeter out.  Here are the details.

It is a 3 pin device.
It consists of a button which first activates the autofocus and then if you press
it further it fires the shutter.  It also has a lock for extended exposures with
the B setting.

There are 3 pins and two switches internally.
Crude ACSII drawing of the connector.
 
	/^\ 
	|1|
	|2|
	|3|
	---

First position - connects pins 1 and 3 and activates the autofocus
Second position, keeps pins 1 and 3 connected and connects pins 1 and 2.
Hence in the second position all pins are connected together.  However
only pins 1 and 2 are needed to fire the shutter.  Just use a double
throw single pole switch (center off) with the common connected to
pin 1.

Have fun at Radio Shack.
Max.