[Linux-parport] Connecting 2 PCs directly over an "8-wire Fast Laplink" cable

Daniel Tahin daniel.t at a1.net
Mon Jun 28 14:35:52 EDT 2004

Thank you for the rash answer:-))

No, of course not. Sorry I forgat to mention, that I don't need a really bi-directional communication. What I need is to set PC A in output-mode and PC B to input-mode, and do a transfer from A to B (like sending data to an external harddisk or printer, that you said). Or is it basically impossible to "simulate" PC B as an paralell external device?

Am 2004.06.28 20:15 schrieb(en) Robert Heller:
>In message <20040628200224.A11439 at pc199.ben.tuwien.ac.at>, Daniel Tahin writes:
>>Hello Developers!
>>Hopefully I'm here right. I would like to ask you about connecing two PCs over
>> a Laplink cable (on the paralell port). But this cable isn't a common Laplink
>> cable that uses only 4 data lines; it uses each (8) data lines. Information a
>>bout cross connecting the cable I put at "http://members.a1.net/e0226781/".
>>It works well under Windows98, with 160-190Kbytes/sec (better than 50Kbytes/se
>>c with the cable that uses only 4 data lines:-))). I would like to ask you, th
>>at is really the highest transfer rate, that could be reached with it? (I ask 
>>you, because I think other paralell devices can do a higher transfer-speed wit
>>h 8 data lines? Or not?)
>>I set the port to ECP, and EPP mode before doing any transfers, but I couldn't
>> go over 190Kbytes/sec.
>The parallel port is a master-slave type of interface -- it is NOT a
>symetrical bi-directional device.  What happens with ALL of the
>'Laplink' parallel port hacks is some sort of hack to 'fake' a full
>duplex interface -- this by its very nature will reduce you effective
>throughput.  With a 'normal' paralell device (eg printer), there is a
>clear master (computer) and slave (printer) relationship and no need to
>fake anything.
>If you really need high-speed bi-directional data transfer, get yourself
>a pair of EtherNet NICs (either PCI cards and/or PCMCIA cards,
>depending).  These cards are cheap enough and easy to get (Radio Shack
>sells them).  With a Cat-5 crossover cable you can skip the switch.
>It might also be possible to get better thn 190Kbytes/sec. thoughput
>with either FireWire or USB 2.0, but I don't know of any PC-to-PC data
>transfer software using either FireWire or USB 2.0.
>>Best regards, and thanx for your answer.
>>Linux-parport mailing list
>>Linux-parport at lists.infradead.org
>                                     \/
>Robert Heller                        ||InterNet:   heller at cs.umass.edu
>http://vis-www.cs.umass.edu/~heller  ||            heller at deepsoft.com
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