[GreenKeys] HAL ST-8000A

[Jack]

ZCZC

I obtained one of the HAL ST-8000A units from
EBAY and it was delivered this past week. I spent
some time checking it out last night after getting
home from another business trip.

The AC connection is a standard "computer" type of
plug, but this unit came with an adaptor from
that standard plug to a mil connector and then a
twist-lock AC plug. So, when you see that the
thing comes with the "special plug", it's not
really needed for the AC connection.

I also received a musty copy of the operator's manual
that lists the external connections and
describes the programming options. This
converter is capable of providing outputs in the
MIL188 or RS232 format. It uses mil-type
multi-pin connectors for this data interface. There is
also a separate mil-type connector for the audio
in and out connections (600 ohm balanced). 

When I plugged the unit in and turned it on, the self-test
display kept repeating itself instead of completing
and then entering the operations mode. I opened up
the top and found a chip was unseated (U2).
One side of the chip was out of the socket...very odd.
Once the chip was plugged back in, the unit passed
the self test and was able to accept input
info from the front keypad. The next test will be
to make sure it accepts input audio and presents it to the
RS232 output, and accepts RS232 input and outputs
the shifted AFSK tones.

The "data" and "audio" multi-pin connectors have short
tails on the inside of the unit that plug into the
main circuit board. Lacking the schematic info,
I will trace the leads to the circuit board so
that I can eventually put RCA jacks on the back for the
audio in and out, and install a standard DB9 connector for the
RS232 connections.

While this particular unit was advertised as "looking
brand new", it wasn't. It appears scrap dealers, mom-and-pop
antique stores, computer repair companies, etc., have tons of
these things. While technically impressive, they are
basic "converters" with features similar to the basic
Dovetrons (no speed conversion). And, they are definitely 
not as "repairable" as the Dovetrons.

Incidentally, the ST-8000A is very similar to the
Frederick/Plantronics 1280, but it appears to have entirely redesigned
innards. My unit has a 1991 manufacture date.

73,
Jack K0TTY

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