NAME
dhu —
DHU-11/DHV-11 serial
communications multiplexer
SYNOPSIS
dhu0 at uba0 csr 0160440
DESCRIPTION
A DHU-11 provides 16 communication lines.
Normal I/O control parameters for individual lines are managed by
ioctl(2) calls. Individual
DHU-11 lines may be configured to run at any of 13 speeds (50, 200 and 38400
baud are not available); the speed may be set via
getty(8) or
stty(1) or may be communicated
by other programs which use
ioctl(2) such as
ifconfig(8), see
tty(4).
The DHU-11 driver normally uses input silos and delays receiver interrupts by 20
milliseconds rather than taking an interrupt on each input character.
FILES
- /dev/tty[S-Z][0-9a-f]
-
NOTES
The driver currently does not make full use of the hardware capabilities of the
DHU-11, for dealing with XON/XOFF flow-control or hard-wired lines for
example.
Although the devices are not the same, a DHU-11 can convince the DH-11
autoconfiguration code that it is a DH-11.
The 4 40-way cables are a pain.
SEE ALSO
tty(4)
HISTORY
The
dhu driver appeared in
4.3BSD.
A new
dhu driver showed up in
NetBSD
1.2.
BUGS
Even if the
dhu hardware supports DMA, the driver cannot make
use of this capability.