[GreenKeys] ASR33 autostart

[Keith Mc]

> Ken Schwieker wrote:
> > Sounds like a fairly simple circuit could accomplish this if other
> > options don't pan out.  Loop current sense into a resettable timer
> > connected to a relay to turn the motor on and off.

Jeffrey D Angus (wa6fwi) wrote: 
> Sounds like a job for our ubiquitous 555 timer set up as a re-trigger 
> able a stable one shot with an opto coupler on the loop side 
> and a relay to drive the motor circuit.
> Jeff-1.0

That's exactly how I did a telephone auto-answer and boot-up circuit
for a remote terminal computer at work, back in the old CP/M 
and early Unix days.  

We were being shut down for a couple of weeks over the 
Christmas break, but I still needed to get some work done
on my project over the holidays.  Since I couldn't take any
of the machines home, I went over to the bench and whipped
up an auto answer circuit, so I could use my TTY and CRT
terminals at home to reach it, with a modem.

I logically wired-ORed together some custom autoanswer 
circuits and the modem's signal lines to retrigger a 555 that 
ran a solid state relay powering my work computer.

When the circuit answered, the machine powered up. 
The circuit held the 555 in retrigger as long as ANY of the
monitored lines said we were still on line and chatting.

Bootup scripts did the rest...

Once I hung up, the 555 started timing out.  This kept the 
power up for at least a few (I think 8?) minutes after hangup, 
at which point the computer powered itself down.  

That gave me time to dial back in before it shut itself off 
should I either change my mind, the line was dropped, 
line noise interrupted my session, or I forgot to do 
something like save and close an edit session before 
hanging up on it.

Of course in those days, as long as you weren't accessing
the disks you could safely just pull the plug on a computer
once done.  Back then you didn't have the problem of 
file corruption or data drop from not syncing up the 
disk drives to worry about, like you often have now with 
Windows or more modern Linux file systems.  

Dial up computers were also so rare that you didn't have 
to really worry about accounts, passwords, etc. on the
cheesy little CP/M machines, and gtty dealt with security 
on the Unix machines.

Now if I were do it again today, I'd have to address 
implementing a more elegant power down ritual.

BTW...The computer was located far enough away to be 
long distance.  Since I got tired of submitting expense reports 
for my phone bill for working at home, I finally wrote a script 
that when run caused the modem to hang up and call ME 
back (using the Hayes command set), so my after hours 
work was on THEIR long distance dime... <grin>  I didn't
sweat the minute or so of LD to call it, to get it to call me back.

Lastly, I later added an old style 24hr mechanical lamp timer 
to the circuit, that I could set it up to trigger and power itself 
on ONCE every 24 hours at the same time, and used a boot 
script to have it call me once upon bootup.  That made it call 
me once per day automatically at the same time, reducing my
LD bill even more, by saving me from having to call IT.

I just unplugged the connection to the timer at work during 
the week, or made sure I didn't answer the phone at that 
time of day on the weekends or vacation when I didn't need 
to chat with it.  Without a successful connect, the 555 would 
then time out and shut the computer down for another 24 
hours, when the lamp timer triggered it on again.

- Keith Mc.