The power from pins 8 and 9 is switched; it is available only when
the CDR220 is turned on. Pin A4 is labelled "Constant 12V". I would
assume that this is always on, use a volt meter to check. Pin A5
ls Antenna trigger, on when the CDR220 is on, and A7 is labelled
"Ignition", probably what turns the CDR220 on. Other than the
pins for C connector I previously listed, I don't know what the
other C pins are in the range 7 - 20. For some of the other connections:

lights on Pin A6 to the CDR220 is called "illumination".
I don't have the specs for this, but suspect that
it directly drives the display brightness level.
You may want to look at this with a voltmeter
and play with instrument brightness to see what
what it does.

tel mute Pin A3 is phone mute, ground to activate.
Note that an external phone would also use
the same inputs you are using for the EMPEG
into the head unit, so you would need some
sort of external switch anyway (discussed
separately somewhere on this board.)
Also, the phone mute probably won't mute
the Aux input, since that is where the phone
would come in.

Earth You can get chassis ground from pin C3.

amp remote You shouldn't need this, since the CDR220
will control the external amp. However,
C6 is "Control output for amplifier", although
I don't know the specs for this. I assume the
CDR220 drives this, so you wouldn't want the
EMPEG to drive it.

memory I have no idea what this is even for!

-gbeck

Still waiting #145xx.....