4.3BSD - /usr/man/cat4/dz.0

DZ(4)                                                                    DZ(4)


NAME
       dz - DZ-11 communications multiplexer

SYNOPSIS
       device dz0 at uba0 csr 0160100 vector dzrint dzxint

DESCRIPTION
       A  DZ11 provides 8 communication lines with partial modem control, ade‐
       quate for UNIX dialup use.  Each line attached to the  DZ11  communica‐
       tions  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 i of flags may be specified for a dz to say  that  a  line  is  not
       properly  connected,  and that the line should be treated as hard-wired
       with carrier always present.  Thus specifying  ‘‘flags  0x04’’  in  the
       specification  of dz0 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

SEE ALSO
       tty(4)

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.


4th Berkeley Distribution        May 16, 1986                            DZ(4)