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Date:      Tue, 2 May 1995 15:27:16 -0700 (PDT)
From:      Julian Elischer <julian@ref.tfs.com>
To:        jgreco@brasil.moneng.mei.com (Joe Greco)
Cc:        nc@ai.net, hackers@FreeBSD.org, FAQ@FreeBSD.org
Subject:   Re: looking for IP over printer port driver users
Message-ID:  <199505022227.PAA09516@ref.tfs.com>
In-Reply-To: <9505022211.AA14225@brasil.moneng.mei.com> from "Joe Greco" at May 2, 95 05:11:54 pm

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it's a laplink cable....
The following comes from the MACH version, which uses the same cable

Poul, Is it still compatible?
can I coonect MACH and FreeBSD?

julian

>From the MACH code we get the following directions:
/*
 Subject: parallel network interface

 The printer network driver has the following hardware requirements for the
 interconnection cable:

 Connections:
 Side1          Side2           Function        Side1    / Side2
 Pin 5          Pin 10  Interrupt strobe: send status (w)/send status (r)
 Pin 2          Pin 15  Data bits       :       write    / read
 Pin 3          Pin 13  Data bits       :       write    / read
 Pin 4          Pin 12  Data bits       :       write    / read
 Pin 6          Pin 11  Data bits       :       write    / read
 Pin 10         Pin 5
 Pin 11         Pin 6
 Pin 12         Pin 4
 Pin 13         Pin 3
 Pin 15         Pin 2
 Pins 18-25     Pins 18-25 (ground interconnections)

 The cable is "symmetric" in that either side can be plugged into either of the
 computers.

 The hardware requirements are as follows:
 Port 0x378 must be writable with the following specifications:
        Bit 4 -> pin 6
        Bit 3 -> pin 5
        Bit 2 -> pin 4
        Bit 1 -> pin 3
        Bit 0 -> pin 2
 Port 0x379 must be readable with the following specifications:
        Bit 7 <- pin 11
        Bit 6 <- pin 10
        Bit 5 <- pin 12
        Bit 4 <- pin 13
        Bit 3 <- pin 15
 Port 0x37a must be readable and writable with the following specifications:
        Bit 4 -> interrupt enable
 So Port 0x378 connects to  Port 0x379 as
        Bit 3 -> pin 5  :  pin 10 -> Bit 6      0x08 -> 0x40

        Bit 4 -> pin 6  :  pin 11 -> Bit 7      0x08<<1 -> ~ 0x80
        Bit 2 -> pin 4  :  pin 12 -> Bit 5      0x07 -> 0x38
        Bit 1 -> pin 3  :  pin 13 -> Bit 4      0x07 -> 0x38
        Bit 0 -> pin 2  :  pin 15 -> Bit 3      0x07 -> 0x38
 [note: bit 0 is considered the least significant bit, pins on the connector
 are numbered starting with 1, -> represents sending data out on the bus, <-
 represents reading data from the bus]

 Pins 1,7,8,9, and 16 are currently unused, and may be allowed to "float".

 The data is sent in 4 bit "nybbles", with the highest 4 bits being sent first.
*/

> 
> > On Thu, 27 Apr 1995, Poul-Henning Kamp wrote:
> > 
> > > > Once I know the rewritten driver is happy,  I'll be adding support for the
> > > > Crynwr/Linux PLIP protocol format.
> > > CooL!
> > 
> > When you have that support going, I can test it for you. I have a linux 
> > box sitting right next to a freebsd box [both run EPP parallel ports] and 
> > move data really well with laplink [under DOS] normally.
> 
> Does anybody have a clue how to manufacture the needed cable?  I would like
> to play with this, but do not want to spend money on a cable that I can
> build from parts in stock..
> 
> ... JG
> 




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