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

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


NAME
     dz - DZ-11 communications multiplexer

SYNOPSIS
     /sys/conf/SYSTEM:
	  NDZ  dz_units  # DZ11; NDZ is in units of boards (8 each)

     /etc/dtab:
	  #Name Unit# Addr   Vector Br Handler(s)      # Comments
	  dz	?     160100 310    5  dzrint  dzdma   # dz11 terminal mux

     major device number:
	  raw: 2
     minor device encoding:
	  bits 0007 specify line on DZ unit
	  bits 0170 specify DZ unit
	  bit  0200 specifies non-blocking open (``CD always on'')

DESCRIPTION
     A DZ11 provides 8 communication lines with partial modem
     control, adequate for UNIX dialup use.  Each line attached
     to the DZ11 communications multiplexer behaves as described
     in tty(4) and may be set to run at any of 16 speeds; see
     tty(4) for the encoding.

     Bit 0200 of the minor device number for DZ lines may be set
     to say that a line is not properly connected, and that the
     line should be treated as hard-wired with carrier always
     present.  Thus creating the special character device node
     "2, 130" via mknod /dev/tty02 c 2 130 would cause line tty02
     to be treated in this way.

     The dz driver monitors the rate of input on each board, and
     switches between the use of character-at-a-time interrupts
     and input silos.  While the silo is enabled during periods
     of high-speed input, the driver polls for input 30 times per
     second.

FILES
     /dev/tty[0-9][0-9]
     /dev/ttyd[0-9a-f]	 dialups
     /dev/MAKEDEV	 script to create special files
     /dev/MAKEDEV.local  script to localize special files

SEE ALSO
     tty(4), dtab(5), autoconfig(8)

DIAGNOSTICS
     dz%d: silo overflow.  The 64 character input silo overflowed
     before it could be serviced.  This can happen if a hard
     error occurs when the CPU is running with elevated priority,
     as the system will then print a message on the console with


Printed 11/26/99	January 28, 1988			1


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


     interrupts disabled.  It is not serious.


Printed 11/26/99	January 28, 1988			2