12 Jul
2024
12 Jul
'24
10:06 p.m.
Ah, the (un)famous "Blue Box" !
I used such a system back in the early 80's. I do not recall which OS
was used, if any. The programming language was PL/M, and the output was
to be burned into an EPROM (2712??)
My system had 3 8" floppy drives, SSSD, 250K , IIRC.
The system we developped (I did the telephone exchange part, another guy
the communication between tower/repeater and the cars) was used for the
gas company, who need for communication between cars, not necessarily
within reach of each other, and the office. The system supported 5-6
simultaneous comminucations between cars, so occupying 10-12 "tasks", 3
local telephone lines (within the office) and IIRC 2 lines into the
normal public system.
The exchange plus communication to/from the towers, could just fit in a
10 x 16 cm Siemens Eurocard, with IIRC 16 K RAM and 16K EPROM (or 32
and 16)
We used normal phones with touch-tone buttons to set up the connection.
In order to break the connection, a special tone was sent when the hook
was put back. This gave some problems, as the tones used for that
purposed, were rather close to the tones used for the "4" button. So
when you dialed a numer with the 4 in it, you never got connected. The
problem was solved with the change of a filter circuit.
it tought me a lot about low-level programmoing.
Nico
Den 2024-07-13 kl. 06:29 skrev Bill Degnan via cctalk:
Just curious what processor and what OS were you
running on it, what model
chassis? You dont hear a lot about MDS systems even in this list
Bill
On Fri, Jul 12, 2024, 11:48 PM Marvin Johnston via cctalk <
cctalk(a)classiccmp.org> wrote:
> In keeping with a previous discussion about reducing a collection size,
> I have an intel MDS system I am kind of looking to sell. This system
> consists of the processor box, dual floppy drives, two keyboards (one
> missing a keycap), and monitor. Unfortunately, no manuals or software
> came with it when I got it some 30 or so years ago. Also I have never
> powered it up and won't since it has been sitting for a long time and
> will need a careful checkout to make sure it is safe to power up.
>
> I do plan on attending VCFMW in early September, and can bring it with
> me (and Sellam) for pickup at the show. My route will be I5 to I80 from
> California so it might be possible for the buyer to make arrangements
> with us to transfer the unit to the buyer along the way. Generally
> speaking, there won't be much time along the way since I generally drive
> 24/7 except for short stops for gas and rest as needed
>
> Long winded way of asking here has anyone a clear idea of what to
> charge. It has been sitting in my garage since I acquired it.
>
> Marvin
>
>