1DMC(4)                     Kernel Interfaces Manual                     DMC(4)
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NAME

6       dmc - DEC DMC-11/DMR-11 point-to-point communications device
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SYNOPSIS

9       /sys/conf/SYSTEM:
10            NDMC dmc_controllers     # DMC11
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DESCRIPTION

13       The  dmc  interface  provides access to a point-to-point communications
14       device which runs at either 1 Mb/s or 56  Kb/s.   DMC-11's  communicate
15       using the DEC DDCMP link layer protocol.
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17       The dmc interface driver also supports a DEC DMR-11 providing point-to-
18       point communication running at data rates from  2.4  Kb/s  to  1  Mb/s.
19       DMR-11's are a more recent design and thus are preferred over DMC-11's.
20       The NXMT and NRCV constants in the driver should be increased  in  this
21       case,  as  the DMR can accept up to 64 transmit and receive buffers, as
22       opposed to 7 for the DMC.
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24       The configuration flags specify how to set up the device,
25       0 -- full duplex DDCMP (normal mode)
26       1 -- DDCMP Maintence mode (generally useless)
27       2 -- DDCMP Half Duplex, primary station
28       3 -- DDCMP Half Duplex, secondary station
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30       Several device error counters are available via "adb", for more  infor‐
31       mation see the adb script /usr/share/adb/dmcstats, or the DMC11 techni‐
32       cal manual.
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34       The host's address must be specified with an SIOCSIFADDR ioctl, and the
35       destination  address  specified with a SIOCSIFDSTADDR ioctl, before the
36       interface will transmit or receive any packets.
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ROUTING

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

46       dmc%d: bad control %o.  A bad parameter was passed to the dmcload  rou‐
47       tine.
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49       dmc%d:  unknown  address  type  %d.  An input packet was received which
50       contained a type of address unknown to the driver.
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52       DMC fatal error 0%o.  A fatal error  in  DDMCP  occurred,  causing  the
53       device to be restarted.
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55       DMC soft error 0%o.  A non-fatal error in DDMCP has occurred.
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57       dmc%d:  af%d  not  supported.  The interface was handed a message which
58       has addresses formatted in an unsuitable address family.
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SEE ALSO

61       intro(4N), inet(4F)
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BUGS

64       The current version of the driver uses a  link-level  encapsulation  so
65       that multiple protocol types may be used.  It is thus incompatible with
66       earlier drivers, including the 4.2BSD version.
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703rd Berkeley Distribution      October 22, 1996                         DMC(4)