Hi; I am attempting to get my zero touch plate going. I do have a 5V on my BOB available, but no input pins available in my ports/pins mach3. I have X Y Z and A (which is a separate stepper on 'Y' axis) Then with the last Input pin used by the E-stop; five allowable, right? Is there any way to open a pin with no added BOB? I've searched and searched for this answer. Seems someone would ask the same question. Maybe I'm not using the right key words..! Thanks

Input pins on Port 1 are: 10, 11, 12, 13, and 15.  Any of these that are unused will work for a touch plate input.   The pins used for X,Y,Z, and A are all outputs.

John Champlain 

Sorry, I wasn't clear, "home switches" on X, Y, Z, A, are occupying those pins. Can those pins be shared? Thanks

Many of Mach3 users use only 1 pin for home and limits, leaving the other pins free for other inputs.  You also have the option of adding a 2nd parallel port.
John Champlain

I'd share the Z home switch with another home switch, then you 'd just home Z first followed by the rest. That frees up the one pin you need,

I failed to mention I use a ESS smoothstepper. But if it works to share pins in Mach, I guess that will make no difference. Thanks, I'll give that a try. Thanks to all.

I'd probably get one of these. http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=482

Ger21, you do know, there are those that get confused with more than three wires coming out of a machine? I really admire these guys, even when their machines look like Frankenstein's monster, they still make sense of it. But I will take your advice if Ports/Pins drive me to drink. Thanks