Re: Kenwood TKR-820
Well...
The logic output is an unbuffered line on the Signaling
unit (the small repeater/ctcss controller board) uP. There
are actually two lines, one labeled TOR and Tone, I believe
they are next to each other. The TOR line comes out to a
small unused solder pad. It's all surface mount circuitry,
so be extra carefull.
[thank you to Juan for the inforatmion about the TOR line]
I tried to measure the transistion of the TOR line with
various types of programming and signaling options. I
could not get the TOR logic to change state.
I have two or three revisions of the tkr-820 manual,
some have different signaling board versions, it's
possible one version might output a valid ctcss "QT"
indication, but I have yet solve that issue.
If your TOR logic functions, it would be possible to
remove R38 (in the normal COR logic line), a zero ohm
jumper/resistor and tie the regular COR logic to the
TOR uP output. This mod is not for the faint of
heart... R38 is a surface mount part on the under
side of the pc board.
The more practical fix:
If you are using one valid ctcss tone, a com spec
decoder on the Descrimnator output pin might be in
order.
I called Kenwood Tech Support (I'm an Authorized
Kenwood Sales & Service Shop) and they faxed me over
a small bit of information related to the accessory
plug and some descriptions of the "W" jumpers on the
Signaling board. But nothing to address a Tone -
Digital Code detect logic output. The Service Manuals
I have here are bit thin on the W3/W4 and various
jumper options. So I've ordered a few sets of new and
current 820/720 repeater service manuals to resolve
the board revision fun.
Pin 13 of the accessory jack outputs a logic transition
with any on frequency rx signal. Be carefull when
interfacing they pin 13 voltage. It's a voltage
transition of about ~ 3.95 volts no signal to about
~ .4 volts with a received signal. It's easy to
damage the circuitry, so a buffer circuit should be
built and used.
I've designed what I call a universal cor circuit,
which doesn't care what voltage transition a logic
output line makes. You connect it to the circuit and
quickly set one simple adjustment. The board output
is known buffered logic output levels and operates
from ~3.5 volt to 32.5 volt supplies without mods.
More on this as the pc boards arrive...
If you'd like to use a tkr-820 or tkr-720 with an
external controller, program the repeater for carrier
squelch, connect the controller to the accessory
jack along with an external ctcss/dcs encoder/decoder
board. There are three "audio output" signals on the
jack, one is discriminator audio, one a gated
receiver audio and the third is rmt speaker output.
Using the above, the Repeat, Monitor and Take-over
buttons on the front panel will be in the "out"
position.
I'll look at the repeater builder text to see if
any additional information is available.
cheers,
skipp
skipp025 at yahoo.com
ps: Email me direct if you need a real hardcopy of
the latest 720/820 manual. I expect to have them in
stock next week.
> "Brent" <[EMAIL PROTECTED]> wrote:
> looking for the ctcss detect connection point on the Kenwoon
TKR-820?
> Anybody know this off hand.
> Thanks
> Brent
>
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