NAME
dhu —
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 ALSO
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.