Why parallel port can't read the digital signal back ?

[API]

Dear all,

             Please help to see my example, that using to control the parallel port digital chain write and read, and I use "Port out.vi and Port in.vi" to do this action, and Port out. vi is OK to control the digital out from Parallel port, but fail to read the digital signal about, what happens ?

and I know the digital read is from 10,11,12,13,15 to ground, and the ground must short from pin 18 to 25. anything that I should do more ? thanks help to tell the thread.

[BeCeGa]

Hi API just to discard hardware troubles have you tried testing the read lines directly on MAX (Measurement and Automation Explorer) through a test panel?

[AndrewAlford]

You are incrementing the address of the read so you are not reading to the port you are writing. Remove the increment from the read address, if you write to x378 then you should read from x378.

[Jeffrey Chen]

Have a try with the following example