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Building the XM1541 Serial Cable

Parts needed:XM1541 cable parts

Visit the ports, parts & pinouts page for a descriptions of all the above parts.

Tools needed:

This is called a "multi-task serial" cable in that it not only works under DOS, but also under multi-tasking OS's such as Windows or GNU/Linux using the proper software like OpenCBM. It uses the same pinout as the XA1541 cable and is compatible with present day parallel ports and modes with a few exceptions. With the switch of two wires, you would have an XE1541 cable. Like the X1541, it is not a difficult cable to build requiring only 4 Schottky diodes instead of the transistor/resistor modules that the XA1541 uses. This cable works with Star Commander, but not with MNIB/NIBTOOLS as you must also have a parallel cable and a parallel port on the 1541/1571 drive.

If you're not sure this is the right cable for you, see my cable picking guide to check.

XM cable copyright Michael Klein & Nicolas Welte, 2000

Step 1: Build the diode modules

Just like the resistor/transistor modules for the XA and XAP, this step creates diode/wire-lead modules which are easy to install on the DB25 connector.

Diodes and wires

First, take the four diodes, cut both ends to about 1/2" (1 cm). Make a small loop in the anodes ends (the ones opposite the ends with the circle all the way around). Strip the wires back about 1/8" (1/2 cm), and twist & tin the wires.

Diodes with wires attached

Second, make a loop in one end of each wire, hook it to the loop of one diode and solder the two together. Cut some 3/32" or 1/8" heat shrink tubing to about 1/2" (1 cm), enough length to cover the wire/diode solder joint and just go over the end of the diode. The heat shrink prevents the diode legs from shorting to each other when soldered to the DB25.

Diodes with wires attached

Third, place the heat shrink tubing over the solder joint and the end of the diode and shrink it on. The modules are now ready to be used.

Step 2: Prep the DIN6 plug and attach the wires

Serial wires in DIN6 Wires attached to the DIN plug.

Step 3: Prepare the DB25 connector and attach the diode modules

Step 4: Attach the wires from the DIN6 serial connector

Step 5: Check the cable

Cable pinout chart

DIN6 (male)
DB25 (male)
2 (GND)
18-25 (GND)
3 (ATN)
4 (CLK)
5 (DATA)
10 (ACK)
11 (BUSY)
13 (SELECT) -->|-- 1 (STROBE)
12 (PAPER END) -->|-- 14 (AUTOFEED)
11 (BUSY) -->|-- 17 (SELECTIN)
10 (ACK) -->|-- 16 (INIT)
18 to 25 shorted

Step 5: Finish the cable. Mount the DB25 end into the hood

Fnished XM1541 cable The completed XM cable.

XM1541 schematic

Schematics drawn using ExpressPCB, a free and excellent solution which also supports PC board layout editing.

Email the author: Peter Schepers | Last updated: June 8, 2009