SOYO SY-6IEB User's Manual & Technical Reference page 23

Hardware Setup
Parallel Port PRT1
This parallel port is used to connect the printer or other parallel
devices.
Your Mainboard comes with one 25-pin female external parallel
connector with 25-pin flat cable.
Plug the 25-pin end of the flat cable into the PRT1 parallel connector
on the Mainboard, as shown in the figure below, then fix the bracket
to one of the slots at the back of the computer case using a screw.
After having finished this you can plug any parallel device into the
back panel connectors.
COM 1
COM 2
PS/2 Mouse
1
1 Connector
FDC
1
PRT 1
AT Keyboard
Plug the keyboard jack directly into the 5-pin female AT keyboard
connector located at the rear panel of the Mainboard.
25-pin parallel
flat cable
KB
Connector
KB
Connector
25-pin female external
AT Keyboard
Connector
20
SY-6IEB
parallel connector