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 NetBSD 1.2.


BUGS

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

NetBSD 10.1                      June 5, 1993                      NetBSD 10.1