2. Hardware required to use PLIP.
The hardware required to set up a PLIP interface is (obviously) a free parallel port in both the machines and the cable. If you can configure it with your BIOS, set it at least as "bi-directional", but if possible in ECP or EPP mode.
About the cable, this is what is written in the plip.c file, in the kernel 2.0.33 source:
The cable used is a de facto standard parallel null cable -- sold as
a "LapLink" cable by various places. You'll need a 12-conductor cable to
make one yourself. The wiring is:
SLCTIN 17 - 17
GROUND 25 - 25
D0->ERROR 2 - 15 15 - 2
D1->SLCT 3 - 13 13 - 3
D2->PAPOUT 4 - 12 12 - 4
D3->ACK 5 - 10 10 - 5
D4->BUSY 6 - 11 11 - 6
Do not connect the other pins. They are
D5,D6,D7 are 7,8,9
STROBE is 1, FEED is 14, INIT is 16
extra grounds are 18,19,20,21,22,23,24
But I strongly advice you to read the /usr/src/linux/drivers/net/README1.PLIP
and README2.PLIP files for more info about the cable.
In my opinion you should avoid building your own parallel null cable. A self-made cable may save very little money, but can add lots of headaches. If you wish to build your parallel cable, remember that you're doing it at your own risk, I reported exactly what is written in plip.c but I don't give warranties.
A final word about cable length: long cables (i.e. more than 10 feet or 3 meters) may bring problems due to radio interference. If you need long cables you should use good and well shielded cables, but very long cables are not recommended: I think the maximal cable lenght should be 15 meters (50 feet).
Anyway, someone mailed me that his/her 100 feet (30 meters) cable works fine; if someone really wants to try a PLIP connection between the office and his/her home (200 meters away), and has the money to spend, can try it, but is at his/her risk.
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