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

NAME
     dz - DZ-11 communications multiplexer

DESCRIPTION
     A dz-11 provides 8 communication lines with partial modem
     control, sufficient for UNIX dialup use.  Each line attached
     to the DZ-11 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.

     DZ lines for which the corresponding minor device numbers
     have the 0200 bit set are treated as having no modem con-
     trol.

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.  If the Berknet _n_e_t(1) is running on a
     _d_z line at high speed (e.g. 9600 baud), there is only 1/15th
     of a second of buffering capacity in the silo, and overrun
     is possible.  This may cause a few input characters to be
     lost to users and a network packet is likely to be cor-
     rupted, but the network will recover.  It is not serious.

Printed 5/17/83                                                 1