History of the term ACU (was: Problems with new 386/ix)

[Eric Schnoebelen]

In article <267 at ndla.UUCP> platt at ndla.UUCP (Daniel E. Platt) writes:
-             Example: if you want to call a system via 'cu <system name>' then
- you need an entry like:
- 
- ACU tty00 - 2400 hayes
- 
- is an entry that tells 'cu' and 'uucico' that 'Auto Call Unix' device at
- 2400 baud uses a 'hayes' dialing sequence.  

        Nit picking and history note time.  ACU does not stand for 'Auto
Call Unix', rather, it is a left over from times past when Mother Bell
did not allow devices other than hers to be connected to the phone
lines, and no modem knew how to dial.  Thus ACU stands (or stood) for
'Automatic Call Unit'.

        A computer could have just a couple of ACUs that it might share
among many outbound modem lines.  The host computer would send a
sequence of commands that would tell the ACU which modem to dial for,
and the number to dial.  Once the dialing was complete, the ACU cut out,
and the modem cut in.  In many ways, it was much nicer, since you didn't
have to worry about all those different modems having different dialing
sequences.  (not to imply that I have actually used such a critter, mind
you, I'm far to young to have ever even seen one :-)

        Useful note:  There is no reason that the devices that dial have
to be named ACU.  They can just as easily be named anything else, such
as Tbit, Metro, Voice, Woof, etc.  The first field of the Devices file
just defines classes of devices, to be matched up with the device class
field of the Systems file.
-- 
Eric Schnoebelen	eric at egsner.cirr.com		schnoebe at convex.com
	"Ford, If I were to ask where in the hell we are, would I
		 regret it?" -- Aurther Dent, HHG