Re: Exploding pagers

On Sat, 21 Sep 2024 12:48:37 -0700, john larkin <JL@gct.com> wrote:

On Sat, 21 Sep 2024 11:03:39 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:
>

On Thu, 19 Sep 2024 14:07:33 -0700, john larkin <jl@650pot.com> wrote:
>
(chomp)

It was probably detonated by some special message, and wouldn't have
worked on a plane.

>
Not all that special.  Pagers made since about 1990 all included a
"group call" feature, where all the pagers in a pre-programmed group
activate simultaneously.  It's normally used to broadcast
announcements:
<https://help.yeastar.com/en/p-series-appliance-edition/administrator-guide/set-up-a-one-way-paging-group.html>
I'm old enough (76) to have been involved with pagers since they
looked and weighed like a small brick and were full of germanium
transistors and vibrating reed tone decoders.

They still needed some way to fire the detonator, sort of a spare port
pin on the uP or whatever is in the pager.

Sure, but that's fairly easy.  The model number of the pager seems to
have been made by:
Gold Apollo Co Ltd
Model number:
AL-A25S

I couldn't find anything on this AL-A25S model, but did find some
useful info on the AL-A26, which seems to be similar.  Actually, I
think I may have one of these pagers:
<https://wiki.recessim.com/view/Apollo_AL-A26_(Pager)>
"The A26 model line is hand-programmable, not requiring any software
to setup basic features (including CAPCODE/RIC, frequency, and
baudrate)..."

Further down the data sheet:
Alerting:
    4 Beep alerts w/ LED flash
    10 Melodic alerts w/ LED flash
    Vibration w/ LED flash
    LED flash only
An external logic circuit and relay driver could trigger on any of
these outputs.  For example, setting the group call to generate one of
the 4 beep alerts, and then decoding the beeps with a relay driver
should work.

As I vaguely recall, there is also an uncommitted test point on the
PCB that can be used to drive a transistor that runs a bell or buzzer.
This is a common configuration for fire departments, where the buzzer
or bell is used to wake up the fireman at night. 

(chomp again)

--
Jeff Liebermann                 jeffl@cruzio.com
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