dn(4) Unsupported dn(4)Namedn - DN-11 autocall unit interface
device dn0 at uba? csr 0160020 vector dnintr
The 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 estab‐
lished, 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
The codes for the phone numbers are:
0-9 dial 0-9
* dial * (`:' is a synonym)
# dial # (`;' is a synonym)
- delay 20 milliseconds
< 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 system call.
By convention, even numbered call units are for 300 baud modem lines,
while odd numbered units are for 1200 baud lines. For example, is
associated with a 300 baud modem line, while is associated with a 1200
baud modem line, For devices such as the Quadracall which simulate mul‐
tiple DN-11 units, the minor device indicates which outgoing modem to
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.
/dev/cua? call units
/dev/cul? associated modem lines