Two standard 2600 controllers at PC parallel port ???

[glaucorocha]

I have seen many sites that teach me how to build an Atari 2600 standard controller working on PC parallel port. But I have to connect 2 controllers (A and B). Is this possible ??? Anyone knows a site that have the eletronic scheme to build it ? I have build two Playstation controllers at parallel port and they work perfectly.

 

Glauco