Waiting for a simple trigger input from parallel port using digitalio

Hello everybody!

I am sucessfully sending a trigger signal through the parallel port using this code:

daq = daqhwinfo('parallel');
dioOut = digitalio('parallel','lpt1');
addline(dioOut,0:7,0,'out');
putvalue(dioOut.line(:),255); % (open trigger)
putvalue(dioOut.line(:),0); % (close trigger)

and then I need to wait for an answer from the connected device, which will send back a simple trigger signal that I try to catch with

dioIn = digitalio('parallel','lpt1');
addline(dioIn,0:7,0,'in');

Check = getvalue(dioIn);

the thing is that I get Check = [0 0 0 0 0 0 0 0] Which is the value set by

putvalue(dioOut.line(:),0);

not the value that my device is sending back to the PC trough the parallel port.

Any idea of how to get this value from the parallel port? It can be sent at any time following the trigger sent as output...

Thxs