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

6       dz - DZ-11 communications multiplexer
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SYNOPSIS

9       /sys/conf/SYSTEM:
10            NDZ  dz_units  # DZ11; NDZ is in units of boards (8 each)
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12       /etc/dtab:
13            #Name Unit# Addr   Vector Br Handler(s)      # Comments
14            dz    ?     160100 310    5  dzrint  dzdma   # dz11 terminal mux
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16       major device number:
17            raw: 2
18       minor device encoding:
19            bits 0007 specify line on DZ unit
20            bits 0170 specify DZ unit
21            bit  0200 specifies non-blocking open (``CD always on'')
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DESCRIPTION

24       A  DZ11 provides 8 communication lines with partial modem control, ade‐
25       quate for UNIX dialup use.  Each line attached to the  DZ11  communica‐
26       tions  multiplexer behaves as described in tty(4) and may be set to run
27       at any of 16 speeds; see tty(4) for the encoding.
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29       Bit 0200 of the minor device number for DZ lines may be set to say that
30       a  line  is not properly connected, and that the line should be treated
31       as hard-wired with carrier always present.  Thus creating  the  special
32       character device node "2, 130" via mknod /dev/tty02 c 2 130 would cause
33       line tty02 to be treated in this way.
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35       The dz driver monitors the rate of input on each  board,  and  switches
36       between  the  use  of  character-at-a-time  interrupts and input silos.
37       While the silo is enabled  during  periods  of  high-speed  input,  the
38       driver polls for input 30 times per second.
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FILES

41       /dev/tty[0-9][0-9]
42       /dev/ttyd[0-9a-f]   dialups
43       /dev/MAKEDEV        script to create special files
44       /dev/MAKEDEV.local  script to localize special files
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SEE ALSO

47       tty(4), dtab(5), autoconfig(8)
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DIAGNOSTICS

50       dz%d:  silo overflow.  The 64 character input silo overflowed before it
51       could be serviced.  This can happen if a hard error occurs when the CPU
52       is running with elevated priority, as the system will then print a mes‐
53       sage on the console with interrupts disabled.  It is not serious.
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573rd Berkeley Distribution      January 28, 1988                          DZ(4)
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