BE: Re: parallel port for data acquisition wrote:
>   port[$378]:=b;       {transmit the byte}
>   b:=port[$378];  {read the parallel port at $378}

I do not know the cable mentioned, but with most cables for parallel port data transfer, output data goes to $378 (or whatever baseaddress you actually have), but only four bits wide. The corresponding four lines are coupled to the four status input pins (hence the four bit limit) of the partner port. These bits may be read back on $379 baseaddr+1, if i am not wrong. Check our cable  or try to write single 0 bit pattern to 378 and look, where the 0s appear on $379.

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