1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)dh.4 8.1 (Berkeley) 6/5/93 33.\" 34.Dd June 5, 1993 35.Dt DH 4 vax 36.Os BSD 4 37.Sh NAME 38.Nm dh 39.Nd 40.Tn DH-11 Ns / Tn DM-11 41multiplexer device interface 42.Sh SYNOPSIS 43.Cd "device dh0 at uba0 csr 0160020 vector dhrint dhxint" Op Ar flags 44.Cd "device dm0 at uba0 csr 0170500 vector dmintr" Op Ar flags 45.Sh DESCRIPTION 46A 47.Tn DH-11 48provides 16 serial communication lines; 49.Tn DM-11 Ns s 50may optionally be 51paired with 52.Tn DH-11 Ns s 53to provide modem control for the lines. 54.Pp 55An optional argument 56.Ar flags 57may be supplied with the device specification 58in the 59.Xr config 8 60file indicating 61that the line corresponding to 62bit number 63.Ar i 64is not properly 65connected, and should be treated as hard-wired with carrier 66always present. Thus specifying 67.Ql flags 0x0004 68for 69.Li dh0 70would cause line 71.Pa ttyh2 72to be treated in this way. 73.Pp 74Normal I/O 75control parameters for individual lines are managed by 76.Xr ioctl 2 77calls. 78Line speeds may be initiated via 79.Xr getty 8 80and 81.Xr stty 1 82or may be communicated by other programs which 83utilize 84.Xr ioctl 85such as 86.Xr ifcongif 8 , 87see 88.Xr tty 4 . 89.Pp 90The 91.Nm dh 92driver monitors the rate of input on each board, 93and switches between the use of character-at-a-time interrupts 94and input silos. 95While the silo is enabled during periods of high-speed input, 96the driver polls for input 30 times per second. 97.Sh FILES 98.Bl -tag -width /dev/tty[h-o][0-9a-f]x -compact 99.It Pa /dev/tty[h-o][0-9a-f] 100.It Pa /dev/ttyd[0-9a-f] 101.El 102.Sh DIAGNOSTICS 103.Bl -diag 104.It dh%d: NXM. 105No response from 106.Tn UNIBUS 107on a dma transfer 108within a timeout period. This is often followed by a 109.Tn UNIBUS 110adapter 111error. This occurs most frequently when the 112.Tn UNIBUS 113is heavily loaded 114and when devices which hog the bus (such as 115.Tn RK07 Ns s) are present. 116It is not serious. 117.Pp 118.It dh%d: silo overflow. 119The character input silo overflowed 120before it could be serviced. This can happen if a hard error occurs 121when the 122.Tn CPU 123is running with elevated priority, as the system will 124then print a message on the console with interrupts disabled. 125It is not serious. 126.El 127.Sh SEE ALSO 128.Xr tty 4 129.Sh HISTORY 130A 131.Nm 132driver appeared in 133.At v6 . 134