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Hello all,

On the GE conversion site I sponsor on rbtip I have information on
the conversion of the Mastr II.


A while back someone told me that the information on the cos that
is suggested for use is not really the best one to use. I believe
the gent said the rus or rui line is a better place because it
follows the Channel Guard and also has some hysteresis built in
when mobiles are in flutter.

What's the consensus?

What is the pin number for RUS or RUI, or what ever the hell it's
called?

I did not originally build the GE Mastr II conversion site on my
server, I inherited it. I am not real well versed on the GE stuff,
but I would like to update this info to be more correct.
I have done several conversions (long ago) on Mastr II's and I
don't even remember what I used.

Thanks,
Kevin

Kevin K. Custer W3KKC wrote:

A while back someone told me that the information on the cos that
is suggested for use is not really the best one to use. I believe
the gent said the rus or rui line is a better place because it
follows the Channel Guard and also has some hysteresis built in
when mobiles are in flutter.

What's the consensus?

What is the pin number for RUS or RUI, or what ever the hell it's
called?

CAS is the 'first' one in line. Carrier Activity Sense. It follows the
receiver regardless of CTCSS/CDCSS. J932 pin 18 is one reference I have
in my notes. I think that is for the base version. I think the mobile is
J904 pin 9.

RUS is the 'second' one in line. Receiver UnSquelched. It only goes high
when the correct CTCSS/CDCSS is present (in addition to the CAS) This
point should be within a few pins of J904 pin 9 (CAS)

I don't have the pin numbers in front of me, but I believe J904 is the
connector they are on. In any case, it is the connector in front of the
audio transformer beside the metering jack. The label right beside the
connector (either mobile or base version) indicates RUS, CAS, and all
other pinouts. It's been a while since I did any interfacing, but if I
recall correctly, CAS will load down *very* easily - even using newer
controllers. It can't source much current. If you don't get them from
someone else, I'll get them at work tomorrow. I've got 4 Micor manuals
here but no Mastr-IIs.

73,
Joe, KR3P

A while back someone told me that the information on the cos that
is suggested for use is not really the best one to use. I believe
the gent said the rus or rui line is a better place because it
follows the Channel Guard and also has some hysteresis built in
when mobiles are in flutter.

I guess that might have been me, Kevin. I use the RX mute line for
the COS signal. Here is my reasoning....

The CAS signal goes high anytime the receiver is active. In other
words, if you are using the factory Channel Guard board for tone
decode, CAS will go high even without the tone.

The RUS line will only go high when the proper tone is decoded,
however, high is on the order of only ~4.0 vdc or so and can sometimes
be tricky about loading. If you use the factory CG board for decode, and
have no need to remote control it on/off, this will work.

BUT....The RX mute line follows the state of tone/carrier squelch. GE
MASTR II's have a CG disable line going to the control head. So....
If you want to use the factory CG board (instead of spending 50 bucks or
so on a TS-32P), and be able to remotely control the tone/carrier squelch,
use the RX mute line for the COS signal, and tie the CG disable to a user
function output on your controller. Grounding the CG disable line will put
the MASTR II into carrier mode, while ungrounding it will put the MASTR II
into tone mode. And the RX mute line will follow this condition.

I am by no means a radio tech, but observations have shown me that the
RX mute line is a little slower acting on rapid squelch flutter. Maybe the
extra circuits slows it down a little.

FWIW, the RX mute will go high (~10 vdc) when the squelch opens, and
0 vdc with the squelch closed. (Darn, I wished I had my manual here!)

The RX mute line supplies 10 vdc to the audio amp from the 10v regulator
(I think?), and will be pulled to ground with no signal. This is to turn
the speaker
on/off, and in essence I am doing the same thing except instead of turning
the controller COS input on/off.

CG disable line simply goes to the mike hang-up box on the control head of
the
GE. So...by putting the CG disable line to an output on the controller, it
is the
same as taking the mike off-hook, which then puts the MASTR II into carrier
mode.

I can't recall the pin # for the RUS line. I do know that it is right
beside the CAS
line on the pins of the IFAS board, and should be labeled accordingly.

The RX mute and the CG disable lines are in the large control cable going
to the control head.


CAS -- Pin # 9 on IFAS board -- Pin #16 on control plug -- Violet wire in
cable

RUS -- Pin #8 on IFAS board -- (ONLY FOUND HERE!)

RX mute -- Pin # 7 on IFAS board -- Pin # 3 on control plug -- yellow/blue
in cable

CG disable -- NOT on IFAS board -- Pin # 6 on control plug -- white/green in
cable

What is the pin number for RUS or RUI, or what ever the hell it's
called?

RUS = Receiver Un Squelched


May be a little bigger answer than you intended, but use what you can.
If I find any errors, I'll let you know...

Henry
KC4KZT

Kevin,

Yes, the RUS ( Receive Unsquelch Sensor ) is the better one to use. It works
with the Channel Guard Decoder ( PL for the Motorola terminology ).
It comes out of the Audio Squelch Board on Pin 8 of P904.

I've worked with the GE Radios for 20 Years now.

John Lloyd, K7JL



Kevin K. Custer W3KKC wrote: