1.\" $NetBSD: dhu.4,v 1.14 2010/04/06 02:30:40 reed 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. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" from: @(#)dhu.4 8.1 (Berkeley) 6/5/93 31.\" 32.Dd June 5, 1993 33.Dt DHU 4 vax 34.Os 35.Sh NAME 36.Nm dhu 37.Nd 38.Tn DHU-11/DHV-11 39serial communications multiplexer 40.Sh SYNOPSIS 41.Cd "dhu0 at uba0 csr 0160440" 42.Sh DESCRIPTION 43A 44.Tn DHU-11 45provides 16 communication lines. 46.Pp 47Normal I/O 48control parameters for individual lines are managed by 49.Xr ioctl 2 50calls. 51Individual 52.Tn DHU-11 53lines may be configured to run at any of 13 speeds 54(50, 200 and 38400 baud are not available); 55the speed may be set via 56.Xr getty 8 57or 58.Xr stty 1 59or may be communicated by other programs which 60use 61.Xr ioctl 2 62such as 63.Xr ifconfig 8 , 64see 65.Xr tty 4 . 66.Pp 67The 68.Tn DHU-11 69driver normally uses input silos 70and delays receiver interrupts by 20 milliseconds 71rather than taking an interrupt on each input character. 72.Sh FILES 73.Bl -tag -width /dev/tty[S-Z][0-9a-f]xx -compact 74.It Pa /dev/tty[S-Z][0-9a-f] 75.El 76.Sh NOTES 77The driver currently does not make full use of the hardware 78capabilities of the 79.Tn DHU-11 , 80for dealing with 81.Tn XON/XOFF 82flow-control or hard-wired 83lines for example. 84.Pp 85Although the devices are not the same, a 86.Tn DHU-11 87can convince the 88.Tn DH-11 89autoconfiguration code that it is a 90.Tn DH-11 . 91.Pp 92The 4 40-way cables are a pain. 93.Sh SEE ALSO 94.Xr tty 4 95.Sh HISTORY 96The 97.Nm 98driver appeared in 99.Bx 4.3 . 100.Pp 101A new 102.Nm 103driver showed up in 104.Nx 1.2 . 105.Sh BUGS 106Even if the 107.Nm 108hardware supports 109.Tn DMA , 110the driver cannot make use of this capability. 111