dhu(4) - NetBSD Manual Pages

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DHU(4)                NetBSD/vax Kernel Interfaces Manual               DHU(4)


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 inter-
     rupts 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 1.2BSD.


BUGS

     Even if the dhu hardware supports DMA, the driver cannot make use of this
     capability.

NetBSD 4.0                       June 5, 1993                       NetBSD 4.0