.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)dn.4 6.1 (Berkeley) 5/15/85
dn \- DN-11 autocall unit interface
.B "device dn0 at uba? csr 0160020 vector dnintr"
device provides an interface through a DEC DN-11 (or equivalent
such as the Able Quadracall) to an auto-call unit (ACU).
To place an outgoing call one forks a sub-process which
opens the appropriate call unit file,
and writes the phone number on it. The parent process
then opens the corresponding modem line
When the connection has been
established, the open on the modem line,
will return and the process will be connected.
A timer is normally used to timeout the opening of
The codes for the phone numbers are:
* dial * (`:' is a synonym)
# dial # (`;' is a synonym)
< end-of-number (`e' is a synonym)
= delay for a second dial tone (`w' is a synonym)
f force a hangup of any existing connection
The entire telephone number must be presented in a single
By convention, even numbered call units are for 300 baud
modem lines, while odd numbered units are for 1200 baud lines.
is associated with a 300 baud modem line,
is associated with a 1200 baud modem line,
For devices such as the Quadracall which simulate multiple DN-11
units, the minor device indicates which outgoing modem to use.
/dev/cul? associated modem lines
Two error numbers are of interest at open time.
The device doesn't exist, or there's no power to it.
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