The X1541-series interfaces

For a complete list of cables and adaptors discussed on these pages, see the cables and adaptors page. If you're having problems with a cable then download XCTest.

The interfaces

There are four serial cables and two additional parallel cables. These all connect Commodore drives to the PC parallel port. Also, using the serial cables, you can connect a Commodore machine to the PC, too. Depending on what Commodore and PC hardware you have, what operating system you are running on your PC and what transfer speed you want to achieve, you may select among a number of cables and cable pairs. For a detailed guide on selecting, see below.

The cables are the following. For more infos on each cable, follow the link on the cable name. For a detailed selection guide, see below.

X1541-series serial cables. These are absolutely necessary, no data transfer will work without them.

  • The X1541 cable is the original cable. It requires an SPP or PS/2 parallel port and it's compatible with all Commodore machines and drives that have the usual serial bus port. However, it's not compatible with the parallel port integrated onto most Pentium and above motherboards.
  • The XE1541 extended cable is a substitute for the X1541 cable. It's also a serial cable and it's also compatible with all Commodore machines and drives that have the usual serial bus port but it works on all parallel ports, including the ones integrated onto most Pentium and above motherboards (see the info page for exceptions!).
  • The XM1541 multitask cable is only a bit different from the XE1541 extended cable. It has two wires swapped at the Commodore end of the cable. This allows other transfer programs to use interrupts rather than polling to do handshake with the Commodore drive under Linux. It's a serial cable, it's compatible with all Commodore machines and drives that have the usual serial bus port and it works on all parallel ports, including the ones integrated onto most Pentium and above motherboards (see the info page for exceptions!).
  • The XA1541 active cable uses transistors and resistors rather than diodes. This makes it the ultimate transfer cable because it works even on those few motherboards that the XE1541 extended cable and the XM1541 multitask cable have problems with. This cable also works under Linux and is compatible with all Commodore machines and drives that have the usual serial bus port.
X1541-series parallel cables. These are optional cables, companions to the serial cables, you can't use them alone. All they do is speed up the data transfer.
  • The XH1541 and XH1571 hybrid cables are companion cables for the X1541 cable. They are compatible with all parallel ports and come in two flavors: the XH1541 hybrid cable for Commodore 1541 drives and the XH1571 hybrid cable for Commodore 1570 and 1571 drives; other drives are not supported. These cables can't be used alone and, effectively, triple the transfer speed in the PC-to-drive direction and speed it up to 150% in the drive-to-PC direction.
  • The XP1541 and XP1571 parallel cables are companion cables for all four serial cables. They are compatible with PS/2, EPP and ECP parallel ports and come in two flavors: the XP1541 parallel cable for Commodore 1541 drives and the XP1571 parallel cable for Commodore 1570 and 1571 drives; other drives are not supported. These cables can't be used alone and, effectively, triple the transfer speed in both the PC-to-drive and the drive-to-PC direction.
X1541-series cable combos. These Y-shaped cables combine a serial cable with a parallel cable.
  • XXH1541 cable combo. A pair of X1541 cable and XH1541 or XH1571 hybrid cable, in the form of a Y-shaped cable.
  • XXP1541 cable combo. A pair of X1541 cable and XP1541 or XP1571 parallel cable, in the form of a Y-shaped cable.
  • XEP1541 cable combo. A pair of XE1541 extended cable and XP1541 or XP1571 parallel cable, in the form of a Y-shaped cable.
  • XMP1541 cable combo. A pair of XM1541 multitask cable and XP1541 or XP1571 parallel cable, in the form of a Y-shaped cable.
  • XAP1541 cable combo. A pair of XA1541 active cable and XP1541 or XP1571 parallel cable, in the form of a Y-shaped cable.
X1541-series adaptors. You can plug a Commodore serial and/or parallel cable into these and then plug the adaptor into the PC. This way, you can use the Commodore cables, that you already have, with a PC, too.
  • XEP1541 adaptor. Serves as a pair of XE1541 extended cable and XP1541 or XP1571 parallel cable, allowing you to reuse your already existing Commodore serial cable and Commodore parallel cable.
  • XMP1541 adaptor. Serves as a pair of XM1541 multitask cable and XP1541 or XP1571 parallel cable, allowing you to reuse your already existing Commodore serial cable and Commodore parallel cable.
  • XAP1541 adaptor. Serves as a pair of XA1541 active cable and XP1541 or XP1571 parallel cable, allowing you to reuse your already existing Commodore serial cable and Commodore parallel cable.
If you'd like to order any of these cables or adaptors then, please, visit The X1541 Shop. If you'd like to buy parts for the cables and adaptors, see the electronical parts page.

Selection guide

If you're interested in technical information about the PC parallel port, the X1541-series cables and the compatibility problems then read the technical background information.

To be able to transfer data between your Commodore drive and your PC, first, you need a serial cable. Note that serial here means that the cable is serial, even if you connect it to the parallel port of the PC. You have four choices: 1) standard X1541 cable; 2) XE1541 extended cable; 3) XM1541 multitask cable; 4) XA1541 active cable. Although their name suggests otherwise, these cables work with most Commodore machines and drives, not only the Commodore 1541 drive.

In any case, you should download X1541Test and test your machine before making a decision. This will tell you whether your parallel port is compatible with the X1541 cable or not. Before running it, check if you can set the mode of your parallel port, either via jumpers on the board or in the BIOS setup. If so, make sure you set it to either SPP or PS/2 because this is what the X1541 cable and X1541Test need. If you can't find these port modes then look out for the settings "Standard", "Compatible" or "Normal" for SPP and "BPP" or "Extended" for PS/2. Don't rely on what your BIOS says about the parallel port mode but rather, after having changed it, check the real mode reported by X1541Test.

On machines that are reported to be incompatible with the X1541 cable, you should use the XE1541 extended cable. Or the XM1541 multitask cable which works under Linux, as well. Unfortunately, there is no way telling with software only whether the XE1541 extended or the XM1541 multitask cable will work on your machine or not. See the info page more details on this incompatibility. If you're out of luck then use the ultimate cable, the XA1541 active cable. This cable works on all PC motherboards and under Linux, as well.

General guidelines for choosing the serial cable are the following.

Case 1. You have a 286, 386 or 486 machine and you're not going to use the cable on any other machine or under Linux. You need the X1541 cable because:

  • The X1541 cable is the easiest of all to build, all the other serial cables need some electronical components.
Case 2. You wish to use the cable (also) on a Pentium or above machine. This machine is not incompatible with the XE1541/XM1541 cables, according to the info pages, and you don't want to use the cable under Linux. You need the XE1541 extended cable because:
  • Most Pentium and above motherboards have an integrated parallel port that is incompatible with the standard X1541 cable.
Case 3. You wish to use the cable (also) on a Pentium or above machine. This machine is not incompatible with the XE1541/XM1541 cables, according to the info pages, and you want to use the cable under Linux. You need the XM1541 multitask cable cable because:
  • Most Pentium and above motherboards have an integrated parallel port that is incompatible with the standard X1541 cable.
  • The XE1541 extended cable is not supported by Linux applications.
Case 4. You wish to use the cable (also) on a Pentium or above machine, which is incompatible with the XE1541/XM1541 cables, according to the info pages. You need the XA1541 active cable, which also works under Linux, because:
  • A few motherboards don't support any of the standard X1541, XE1541 extended or XM1541 multitask cables.
If you have the serial cable finished and the transfer program up and running with it and you have a Commodore 1541, 1570 or 1571 drive or compatible clone, you can think of speeding the transfer up with one of the additional cables. Please, note that all these cables need modifications in your Commodore drive. If you're not good at hardware hacking, don't try doing it yourself but ask for an expert's help instead. Also, read the transfer program's documentation on whether it supports these cables. You have two choices: 1) XH1541/XH1571 hybrid cable; 2) XP1541/XP1571 parallel cable. Both come in two slightly different flavors: one for Commodore 1541 drives, the other for Commodore 1570 and 1571 drives.

If you only have one parallel port then there are several cases, depending on what serial cable you already have connected to what parallel port.

Case 1. You have an SPP port and you're using the X1541 cable on it. The XH1541 and XH1571 hybrid cables give you an additional semi-parallel connection on this configuration because:

  • The XP1541 and XP1571 parallel cables don't work on an SPP port.
Case 2. You have an SPP port and you're using the XE1541 extended, XM1541 multitask or XA1541 active cable on it. There are no possible enhancements on this configuration because:
  • The pin layout of the XH1541 and XH1571 hybrid cables conflicts with that of the XE1541 extended, XM1541 multitask and XA1541 active cables.
  • The XP1541 and XP1571 parallel cables don't work on an SPP port.
Case 3. You have a PS/2 port and you're using one of the serial cables on it. The XP1541 and XP1571 parallel cables give you an additional parallel connection on this configuration because:
  • The XH1541 and XH1571 hybrid cables don't give you the maximum speed possible on a PS/2 port.
Case 4. You have an EPP or ECP port and you're using the XE1541 extended, XM1541 multitask or XA1541 active cable on it. The XP1541 and XP1571 parallel cables give you an additional parallel connection on this configuration because:
  • The XH1541 and XH1571 hybrid cables don't give you the maximum speed possible on an EPP or ECP port and they have a layout that conflicts with the XE1541 extended, XM1541 multitask and XA1541 active cables anyway.
If you have two parallel ports then you can choose among the additional cables independently of the mode of your first parallel port and the serial cable you already have.

Case 1. Your second parallel port is an SPP port. The XH1541 and XH1571 hybrid cables give you an additional semi-parallel connection on this configuration because:

  • The XP1541 and XP1571 parallel cables don't work on an SPP port.
Case 2. Your second parallel port is a PS/2, EPP or ECP port. The XP1541 and XP1571 parallel cables give you an additional parallel connection on this configuration because:
  • The XH1541 and XH1571 hybrid cables don't give you the maximum speed possible on an EPP or ECP port.

Source: The Joe Forster-STA homepage

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