Re: A Null Printer Cable for PLIP
Hello
What kinds of problems do you have exactly?
> How to make ___WORKING___ Null Printer Cable for use with a PLIP
> connection?
On my woody installation, I found two howtos and one kernel
documentation.
/usr/share/doc/HOWTO/en-txt/mini/PLIP.gz
/usr/share/doc/HOWTO/en-txt/PLIP-Install-HOWTO.gz
/usr/src/kernel-source-2.4.17/Documentation/networking/PLIP.txt
Quoting PLIP.txt:
Parallel Transfer Mode 0 Cable
==============================
The cable for the first transfer mode is a standard
printer "null" cable which transfers data four bits at a time using
data bit outputs of the first port (machine T) connected to the
status bit inputs of the second port (machine R). There are five
status inputs, and they are used as four data inputs and a clock (data
strobe) input, arranged so that the data input bits appear as contiguous
bits with standard status register implementation.
A cable that implements this protocol is available commercially as a
"Null Printer" or "Turbo Laplink" cable. It can be constructed with
two DB-25 male connectors symmetrically connected as follows:
STROBE output 1*
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
D5,D6,D7 are 7*, 8*, 9*
AUTOFD output 14*
INIT output 16*
SLCTIN 17 - 17
extra grounds are 18*,19*,20*,21*,22*,23*,24*
GROUND 25 - 25
* Do not connect these pins on either end
If the cable you are using has a metallic shield it should be
connected to the metallic DB-25 shell at one end only.
Parallel Transfer Mode 1
========================
The second data transfer method relies on both machines having
bi-directional parallel ports, rather than output-only ``printer''
ports. This allows byte-wide transfers, and avoids reconstructing
nibbles into bytes. This cable should not be used on unidirectional
``printer'' (as opposed to ``parallel'') ports or when the machine
isn't configured for PLIP, as it will result in output driver
conflicts and the (unlikely) possibility of damage.
The cable for this transfer mode should be constructed as follows:
STROBE->BUSY 1 - 11
D0->D0 2 - 2
D1->D1 3 - 3
D2->D2 4 - 4
D3->D3 5 - 5
D4->D4 6 - 6
D5->D5 7 - 7
D6->D6 8 - 8
D7->D7 9 - 9
INIT -> ACK 16 - 10
AUTOFD->PAPOUT 14 - 12
SLCT->SLCTIN 13 - 17
GND->ERROR 18 - 15
extra grounds are 19*,20*,21*,22*,23*,24*
GROUND 25 - 25
* Do not connect these pins on either end
Once again, if the cable you are using has a metallic shield it should
be connected to the metallic DB-25 shell at one end only.
HTH, chl
--
Dipl. Phys. Carsten Lechte
Institut fuer Experimentelle und Angewandte Physik
Christian-Albrechts-Universitaet, 24098 Kiel, Germany
http://www.ieap.uni-kiel.de/plasma/ag-stroth
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