DZ(4)

NAME
dz - DZ-11 serial multiplexer device interface

SYNOPSIS
dz0 at uba0 csr 0160100 vector dzrint dzxint

DESCRIPTION
A DZ-11 provides 8 communication lines with partial modem control, adequate 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 carrier 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 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

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.

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

HISTORY
A dz driver appeared in AT&T UNIX.