The XP1541 parallel cable and the XP1571 parallel cable are companion cables for the X1541 cable, the XE1541 extended cable, the XM1541 multitask cable and the XA1541 active cable, to get the most possible out of PS/2, EPP and ECP ports, creating an additional parallel connection between a Commodore 1541, 1570 or 1571 drive and the PC parallel port. This parallel connection speeds up both transfer directions to about triple speed (the actual value depends on the transfer software, as well). They are compatible with PS/2, EPP and ECP parallel ports and come in two flavors: the XP1541 parallel cable for 1541 drives and the XP1571 parallel cable for 1570 and 1571 drives.
You need the following hardware to make use of this cable:
A Commodore 1541, 1570 or 1571 drive or compatible clone
The cable is supported by the following PC software:
The Star Commander (© by Joe Forster/STA, 1994-2005)
Don't let the name "XP1571" fool you. This cable flavor also works with Commodore 1570 drives, not only Commodore 1571 drives. The other "XP1541" flavor is for Commodore 1541 drives only.
This cable needs 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.
This cable is rather a concept than an actual cable. If you build it as described in methods #1 and #2, you will be able to use the parallel capabilities of your Commodore drive only from a PC, but not from a Commodore machine. Method #3 is solves this problem but you would still need two parallel ports – one for the serial cable and one for this cable –, unless you build one of the X1541-series cable combos instead.
Your best choice is method #4, which implements the concept as a Commodore parallel cable plugged into an X1541-series adaptor. This way, the drive can be connected to a Commodore machine, via the Commodore parallel cable alone, as well as to a PC, via the cable plugged into the adaptor which needs only one parallel port.
Although the recommended implementation of this cable is a Commodore parallel cable and an X1541-series adaptor, this cable does not connect the hardware handshake lines (PC2 and FLAG2) of the Commodore parallel cable to any pin on the PC parallel port. As the software emulation of hardware handshake is quite impossible on a PC, software handshake is used on the accompanying X1541-series serial cable instead.
This cable is a companion, it doesn't work alone. On a PS/2 port, you can use it along with any of the four serial cables; on an EPP or ECP port, the X1541 cable is ruled out becuase it doesn't work on such ports.
This cable contains no GND connection because the serial cable already has one. Multiple GND connections may result in a "ground loop", when current is flowing between the two machines via the GND lines. This can cause not only unreliable behavior but also damage to your equipment. It may be possible to filter the GND lines so that they fulfill their primary purpose but not create a ground loop, however, such solutions may be relatively complicated and expensive.
There are several methods to build this cable. You may share the parallel port between this cable and any of the four serial cables – X1541 cable, XE1541 extended cable, XM1541 multitask cable or XA1541 active cable – by building a Y-shaped cable and soldering the extra connections of this cable onto the parallel port plug you already have. See the XEP1541 cable combo, the XMP1541 cable combo or the XAP1541 cable combo for more details.
Method 1. Your drive has no parallel capabilities yet and you want to connect the cable directly onto the periphery chip in the drive. If possible, you shouldn't use this method because, this way, you won't be able to make use of it with a Commodore machine. You can find the details on how to build this cable at the construction page for 1541 drives and the construction page for 1570 and 1571 drives.
Method 2. Your drive has no parallel capabilities yet and you want to create a parallel port on your drive and then connect the cable to it. This is the preferred method because you can also make use of it with a Commodore machine. You can find the details on how to build this cable at the construction page.
If you have successfully finished the parallel port on your drive then you can also build the Commodore parallel cable, to use the parallel capabilities with a Commodore machine.
Method 3. Your drive already has a Commodore parallel cable and you want to make use of it. In this case, you'll have to build an adaptor, through which you can connect the cable to the PC parallel port. You can find the details on how to build this adaptor at the construction page.
Method 4. The XEP1541 adaptor, besides serving as an XE1541 extended cable, adapts a Commodore parallel cable for use with a PC. So do the XMP1541 adaptor and the XAP1541 adaptor.
If you built a cable and you created or already have a parallel port on your Commodore drive then you can connect one end of the cable into it; otherwise the cable is, probably, just hanging out of the drive. If you built an adaptor then connect the user port plug onto it, being very careful to exactly do it upside down, that is, the top side of the user port plug should be leveled with that side of the adaptor without circuitry. In any case, connect the parallel plug of your cable or adaptor into the parallel port of your PC.
Important! Do not plug or unplug cables while your equipment is switched on. Make sure that all components of your equipment are connected to the same, properly grounded power outlet. Put your equipment far away from monitors, TV sets and other devices with strong emission, otherwise cables may pick up interference and you may experience data loss or corruption. Never leave this cable connected alone, only if the serial cable is also connected, otherwise the lack of GND connection may severely damage your equipment.
The XP1541 and XP1571 parallel cables are © by Joe Forster/STA, 1997. If you produce and sell cables or adaptors that are compatible with this cable then you must give credits to the copyright owner. If your adaptors are built onto printed circuit boards then you must also make the complete layout available in a format and resolution that is suitable for high quality reproduction.
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