DZ(4)                  OpenBSD Programmer's Manual (VAX)                 DZ(4)

NAME
     dz - DZ-11 multiplexer device interface

SYNOPSIS
     device dz0 at uba0 csr 0160100 vector dzrint dzxint

DESCRIPTION
     A DZ-11 provides 8 communication lines with partial modem control, ade-
     quate for UNIX dialup use.

     An optional argument flags may be supplied with the device specification
     in the config file indicating that the line corresponding to bit number i
     is not properly connected, and should be treated as hard-wired with car-
     rier always present.  Thus specifying `flags 0x04' for dz0 would cause
     line tty02 to be treated in this way.

     Normal I/O control parameters for individual lines are managed by
     ioctl(2) calls.  Line speeds may be initiated via the ttys(5) file,
     stty(1) or ifconfig(8) to name a few, see tty(4).

     The dz driver monitors the rate of input on each board, and switches be-
     tween 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

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 mes-
     sage on the console with interrupts disabled.  It is not serious.

SEE ALSO
     stty(1),  tty(4),  ttys(5),  getty(8)

HISTORY
     A dz driver appeared in Version 32V AT&T UNIX.

OpenBSD 2.6                     March 27, 1991                               1
