DHU(4) OpenBSD Programmer's Manual (VAX) DHU(4)NAMEdhu - DHU-11/DHV-11 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 utilize 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 ALSOtty(4), uba(4)HISTORY
The dhu driver appeared in 4.3BSD. A new dhu driver showed up in
NetBSD 1.1a.
BUGS
Even if the dhu hardware supports DMA, the driver cannot make use of this
capability.
OpenBSD 4.9 May 31, 2007 OpenBSD 4.9
