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
