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DMC(4)                NetBSD/vax Kernel Interfaces Manual               DMC(4)


NAME

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


SYNOPSIS

     dmc0 at uba0 csr 167600


DESCRIPTION

     NOTE: This driver has not been ported from 4.4BSD yet.

     The dmc interface provides access to a point-to-point communications
     device which runs at either 1 Mb/s or 56 Kb/s.  DMC-11s communicate using
     the DEC DDCMP link layer protocol.

     The dmc interface driver also supports a DEC DMR-11 providing point-to-
     point communication running at data rates from 2.4 Kb/s to 1 Mb/s.
     DMR-11s are a more recent design and thus are preferred over DMC-11s.
     The NXMT and NRCV constants in the driver may 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 Maintenance mode (generally useless)
           2      DDCMP Half Duplex, primary station
           3      DDCMP Half Duplex, secondary station

     The host's address must be specified with an SIOCSIFADDR ioctl(2), and
     the destination address specified with a SIOCSIFDSTADDR ioctl(2), 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(2).  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 rou-
     tine.

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

     DMC fatal error 0%o.  A fatal error in DDMCP occurred, causing 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 message which has
     addresses formatted in an unsuitable address family.


SEE ALSO

     inet(4), intro(4)


HISTORY

     The dmc driver appeared in 4.2BSD.


BUGS

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

NetBSD 5.2.3                     June 5, 1993                     NetBSD 5.2.3