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.