1.\" $NetBSD: dhu.4,v 1.10 2002/01/15 02:07:39 wiz Exp $ 2.\" 3.\" Copyright (c) 1985, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)dhu.4 8.1 (Berkeley) 6/5/93 35.\" 36.Dd June 5, 1993 37.Dt DHU 4 vax 38.Os 39.Sh NAME 40.Nm dhu 41.Nd 42.Tn DHU-11/DHV-11 43serial communications multiplexer 44.Sh SYNOPSIS 45.Cd "dhu0 at uba0 csr 0160440" 46.Sh DESCRIPTION 47A 48.Tn DHU-11 49provides 16 communication lines. 50.Pp 51Normal I/O 52control parameters for individual lines are managed by 53.Xr ioctl 2 54calls. 55Individual 56.Tn DHU-11 57lines may be configured to run at any of 13 speeds 58(50, 200 and 38400 baud are not available); 59the speed may be set via 60.Xr getty 8 61or 62.Xr stty 1 63or may be communicated by other programs which 64utilize 65.Xr ioctl 2 66such as 67.Xr ifconfig 8 , 68see 69.Xr tty 4 . 70.Pp 71The 72.Tn DHU-11 73driver normally uses input silos 74and delays receiver interrupts by 20 milliseconds 75rather than taking an interrupt on each input character. 76.Sh FILES 77.Bl -tag -width /dev/tty[S-Z][0-9a-f]xx -compact 78.It Pa /dev/tty[S-Z][0-9a-f] 79.El 80.Sh NOTES 81The driver currently does not make full use of the hardware 82capabilities of the 83.Tn DHU-11 , 84for dealing with 85.Tn XON/XOFF 86flow-control or hard-wired 87lines for example. 88.Pp 89Although the devices are not the same, a 90.Tn DHU-11 91can convince the 92.Tn DH-11 93autoconfiguration code that it is a 94.Tn DH-11 . 95.Pp 96The 4 40-way cables are a pain. 97.Sh SEE ALSO 98.Xr tty 4 99.Sh HISTORY 100The 101.Nm 102driver appeared in 103.Bx 4.3 . 104.br 105A new 106.Nm 107driver showed up in 108.Bx 1.2 . 109.Sh BUGS 110Even if the 111.Nm 112hardware supports 113.Tn DMA , 114the driver cannot make use of this capability. 115