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 _d_m_c__c_o_n_t_r_o_l_l_e_r_s	   # DMC11

DESCRIPTION
     The _d_m_c 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 _d_m_c 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 _r_o_u_t_e(8) command,
     or by the use of the routing process _r_o_u_t_e_d(8) on each end
     of the link.

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