How to build MB Star C3 Part D RS232 Cable (Pinout)

This is a DIY how-to’s of RS232 cable for MB Star C3 multiplexer.

C3 is name for cloned Part D

There are 4 types of cable (or more but those 4 are known to me)
2 with board
2 without boards

graphic drawing with pin-outs
and how to disassemble round plug

Rs232 Cable with board:

Cable without board:

1 unscrew the black cable retainer

2 unscrew insert

3 insert plug into Part D

4 unscrew left housing A

Note: Part D is loose and don’t take part in disassemble

inner pin out on old C3.
where 18 pin connector (laptop side) is connected to 10PB031B board.

For this MB STAR C3 type when you using cable with MAX you need Type B from second drawing.

If you’re not equipped with knowledge /experience or the cable you made is unluckily broken to death, you’d better spend a few dollars with a finished product.


This is thebest-qualityRS232-RS485 cablewith golden box: