2.11BSD#431 - /usr/man/cat4/dmc.0

DMC(4)		    UNIX Programmer's Manual		   DMC(4)


NAME
     dmc - DEC DMC-11/DMR-11 point-to-point communications device

SYNOPSIS
     /sys/conf/SYSTEM:
	  NDMC dmc_controllers	   # DMC11

DESCRIPTION
     The dmc interface provides access to a point-to-point com-
     munications device which runs at either 1 Mb/s or 56 Kb/s.
     DMC-11's communicate using the DEC DDCMP link layer proto-
     col.

     The dmc interface driver also supports a DEC DMR-11 provid-
     ing point-to-point communication running at data rates from
     2.4 Kb/s to 1 Mb/s.  DMR-11's are a more recent design and
     thus are preferred over DMC-11's.	The NXMT and NRCV con-
     stants in the driver should be increased in this case, as
     the DMR can accept up to 64 transmit and receive buffers, as
     opposed to 7 for the DMC.

     The configuration flags specify how to set up the device,
     0 -- full duplex DDCMP (normal mode)
     1 -- DDCMP Maintence mode (generally useless)
     2 -- DDCMP Half Duplex, primary station
     3 -- DDCMP Half Duplex, secondary station

     Several device error counters are available via "adb", for
     more information see the adb script /usr/share/adb/dmcstats,
     or the DMC11 technical manual.

     The host's address must be specified with an SIOCSIFADDR
     ioctl, and the destination address specified with a SIOC-
     SIFDSTADDR ioctl, before the interface will transmit or
     receive any packets.

ROUTING
     The driver places a HOST entry in the kernel routing tables
     for the address given in the SIOCSIFDSTADDR ioctl.  To use
     the DMC as a link between local nets, the route to the
     remote net must be added manually with the route(8) command,
     or by the use of the routing process routed(8) on each end
     of the link.

DIAGNOSTICS
     dmc%d: bad control %o.  A bad parameter was passed to the
     dmcload routine.

     dmc%d: unknown address type %d.  An input packet was
     received which contained a type of address unknown to the
     driver.


Printed 11/26/99	October 22, 1996			1


DMC(4)		    UNIX Programmer's Manual		   DMC(4)


     DMC fatal error 0%o.  A fatal error in DDMCP occurred, caus-
     ing the device to be restarted.

     DMC soft error 0%o.  A non-fatal error in DDMCP has
     occurred.

     dmc%d: af%d not supported.  The interface was handed a mes-
     sage which has addresses formatted in an unsuitable address
     family.

SEE ALSO
     intro(4N), inet(4F)

BUGS
     The current version of the driver uses a link-level encapsu-
     lation so that multiple protocol types may be used.  It is
     thus incompatible with earlier drivers, including the 4.2BSD
     version.


Printed 11/26/99	October 22, 1996			2