Hi,

I have found 1 interesting circuit on the web.

http://www.zen22142.zen.co.uk/Circuits/Interface/pethhub.htm

Do anyone know the function of diodes in the circuit?
I just don't understand why the diodes are arranged in pairs, in opposite direction. So what is the diference if all diodes is removed?

Thanks!

 

Help!!! anyone have idea??

 

The only thing I can think of is a signal has to reach a certain threshold to be heard by the other computers. Personally I'm dubious, but if it works...

 

This is an example of Diode - Resistor Logic circuitry.

http://en.wikipedia.org/wiki/Diode_logic

The diodes are connected 'back to back' to respond to positive and negative going signals.

Early computer logic circuits were constructed like this, with boards containing thousands of diodes.

The same idea was later incorporated into integrated circuits as multiple emitter transistor gates in TTL.

Hope this helps