PLIP(4)               OpenBSD Programmer's Manual (PC532)              PLIP(4)

NAME
     plip - Option for the lpt driver to allow IP over centronics ports

SYNOPSIS
     options PLIP
     options COMPAT_PLIP10
     options COMPAT_PLIP11

DESCRIPTION
     The plip interface provides a way to transport IP over centronics ports.
     Protocols to communicate with Linux 1.0 and Linux 1.1 hosts are provided.
     By default the 1.1 protocol is used. To choose the 1.0 protocol use the
     link0 flag with ifconfig(8) or in your /etc/hostname.plip? file. In order
     to use the 1.0 protocol the kernel has to be compiled with COMPAT_PLIP10.
     The COMPAT_PLIP11 option selects a default MTU of 1486 bytes. This is
     necessary to work around a bug that is present in the plip code for Linux
     1.1.x and Linux 1.2.x.

NOTES
     To connect two computers a "Laplink parallel cabel" is used:

     +-----------+-------+-------+---------------------+
     |Signalname | Con A | Con B |     Description     |
     +-----------+-------+-------+---------------------+
     |Data 0     |     2 |    15 | Data out 0          |
     +-----------+-------+-------+---------------------+
     |Data 1     |     3 |    13 | Data out 1          |
     +-----------+-------+-------+---------------------+
     |Data 2     |     4 |    12 | Data out 2          |
     +-----------+-------+-------+---------------------+
     |Data 3     |     5 |    10 | Data out 3/Wake out |
     +-----------+-------+-------+---------------------+
     |Data 4     |     6 |    11 | Data clock out      |
     +-----------+-------+-------+---------------------+
     |/Ack       |    10 |     5 | Data in 3/Wake in   |
     +-----------+-------+-------+---------------------+
     |Busy       |    11 |     6 | Data clock in       |
     +-----------+-------+-------+---------------------+
     |No Paper   |    12 |     4 | Data in 2           |
     +-----------+-------+-------+---------------------+
     |Select     |    13 |     3 | Data in 1           |
     +-----------+-------+-------+---------------------+
     |/Error     |    15 |     2 | Data in 0           |
     +-----------+-------+-------+---------------------+
     |Gnd        | 18-25 | 18-25 | Ground              |
     +-----------+-------+-------+---------------------+
     In both protocol versions ethernet frames are used. The 1.0 protocol as-
     signs an ethernet address of the form FD:FD:ww:xx:yy:zz to the interface.
     The 1.1 protocol uses FC instead of FD. ww, xx, yy and zz are taken from
     the internet address ww.xx.yy.zz of the interface. Ethernet support has
     to be configured into the kernel in order to use the plip interface.

SEE ALSO
     lpt(4) ifconfig(8)

DIAGNOSTICS
     plip?: tx hard error  Packet transmission failed even after PLIPMXRETRY
     (20) retries.

     plip?: rx hard error  PLIPMXERRS (20) packets caused receive errors in
     sequence.


     plip?: checksum error  A packet with a bad checksum was received.

     plip?: packet > MTU  A bogus packet longer than the MTU was received.

OpenBSD 2.6                    December 1, 1994                              2
