The XA1541 active cable
You should follow these instructions if you want to put the electronical parts onto a mini-adaptor, which you can hide inside the case of the parallel port plug.
First, create the XA1541 mini-adaptor.
You need the following parts to build this cable:
Step 1. Solder one end of the cable onto the DIN plug.
Step 2. Solder the other end of the cable onto the XA1541 mini-adaptor port. These include the following connections:
You can find the description of all parts used on the diagrams at the legend page.
Source: The Joe Forster-STA homepage