DN(4)                  OpenBSD Programmer's Manual (VAX)                 DN(4)

NAME
     dn - DN-11 autocall unit interface

SYNOPSIS
     device dn0 at uba? csr 0160020 vector dnintr

DESCRIPTION
     The dn 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 out-
     going call one forks a sub-process which opens the appropriate call unit
     file, /dev/cua? and writes the phone number on it.  The parent process
     then opens the corresponding modem line /dev/cul?. When the connection
     has been established, the open on the modem line /dev/cul? will return
     and the process will be connected.  A timer is normally used to timeout
     the opening of the modem line.

     The codes for the phone numbers are:

           0-9     number to be dialed
           *       dial * (`:' is a synonym)
           #       dial # (`;' is a synonym)
           -       delay 20 milliseconds
           <       end of phone number (`e' is a synonym)
           =       delay for a second dial tone (`w' is a synonym)
           f       force a hangup of any existing connection

     The phone number to be dialed must be presented as one contiguous string.

     By convention, even numbered call units are for 300 baud modem lines,
     while odd numbered units are for 1200 baud lines.  For example, /dev/cua0
     is associated with a 300 baud modem line, /dev/cul0, while /dev/cua1 is
     associated with a 1200 baud modem line, /dev/cul1. For devices such as
     the Quadracall which simulate multiple DN-11 units, the minor device in-
     dicates which outgoing modem to use.

FILES
     /dev/cua?  call units
     /dev/cul?  associated modem lines

DIAGNOSTICS
     Two error numbers are of interest at open time.

     [EBUSY]  The dialer is in use.

     [ENXIO]  The device doesn't exist, or there's no power to it.

SEE ALSO
     tip(1)

HISTORY
     A dn driver appeared in Version 6 AT&T UNIX.

OpenBSD 2.9                     March 27, 1991                               1
