On Fri, 19 May 2017, John Labovitz via cctalk wrote:
Another BBS obscurity ?
I ran a BBS in the early 80s called The Bethesda RCP/M. Those of us who
couldn?t afford dedicated lines often used a method called ?ringback.?
This was a clever way to share a regular home phone with a modem.
The idea was that if you wanted to dial up to the BBS, you?d call my
number, but hang up after one ring, then call back. The software (BYE,
as someone else here mentioned) would be monitoring the ring-detect line
on the modem?s serial port, and watch for ring patterns. If it saw a
second ring within ~4 seconds, it would ignore the call, assuming it was
a voice call; otherwise, it would send the Hayes code to answer the line
(ATA). It?s weird how I still remember all that logic, 35 years later...
I recall seeing the feature in BYE, but this is the first time I've heard
of someone using it. Neat! :)
For those that don't know what BYE is, it's basically a fancy I/O
redirector for CP/M. It would handle the serial comms and a few other
things, and redirect I/O from the serial port, to the console. This meant
that you could run BBS software that didn't have any serial I/O. The
first versions of RBBS were like this - simply compiled BASIC with regular
INPUT and PRINT statements.
BYE was written in 8080 assembly (I think MBYE was Z-80, but I'm not sure)
and used an "insert" for the type of computer you were going to use it on.
The insert contained code for all the machine-specific features that BYE
needed (serial port control, 25th line support for status bar, etc.).
At some point a version of BYE was created for the IBM PC, but as far as I
know, there was only a single release of it.
g.
--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby. Geeks collect hobbies.
ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!