4.3BSD-UWisc/man/cat4/dz.4

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DZ(4)               UNIX Programmer's Manual                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, adequate for UNIX dialup use.  Each line attached
     to the DZ11 communications multiplexer behaves as described
     in _t_t_y(4) and may be set to run at any of 16 speeds; see
     _t_t_y(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 _d_z 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 message on the console with
     interrupts disabled.  It is not serious.

















Printed 12/27/86          May 16, 1986                          1