[Motorola] CDM750 accessory connector/ RX audio

Sun, 10 Nov 2002 09:17:09 -0800

Bill,

I'm not sure I see a problem here, since a remote tone adapter normally
requires flat and unmuted audio in order to work properly.

Unmuted audio is always available at Pin 11 of the CDM-750 accessory
connector, and it will be either be flat (discriminator) audio or
filtered (de-emphasized) audio, depending upon the selection of "Rx
Audio Type" on the Accessory Configuration tab of the Radio
Configuration page.  This should be set to "Flat Audio" when an outboard
tone controller is used.  Either output is a constant level, independent
of the volume control.

If you must mute this audio, you can use one of the programmable
accessory pins set for "CSQ Detect" or "PL and CSQ Detect" to control a
CMOS audio switch.  But, I can't imnagine needing to do this with an
outboard tone controller- and doing so will likely interfere with its
operation.  (I probably am making assumptions without having all the
facts.)

By the way, if you have the latest version of CPS, R06.02.03, you now
have the capability of selecting "Non-Standard Reverse Burst" on a
per-channel basis.  The selection is made on the "Advanced" tab of the
Conventional Personality page.  When the box is unchecked, its default,
the PL reverse burst is set for the Motorola format.  When the box is
checked, the reverse burst is encoded and decoded in the Kenwood format-
used by all other major radio brands and aftermarket tone units.  I have
an HT-750 radio that I use in more than one repeater system- two are
Kenwood, and the rest are Motorola.  Being able to program the reverse
burst to mute silently in all systems is a HUGE improvement!  If your
remote tone adapter does not mute silently, that is, you get a "squelch
crash" when receiving from a Motorola radio, try the Non-Standard
Reverse Burst.  It really does work.

73, Eric Lemmon WB6FLY

William F Morphy wrote:
> 
> My company bought a CDM750 with PS and Remote Tone Adapter.  I can't set
> up the radio to properly mute / unmute RX audio on PL or CSQ from any
> accessory connector pins.
> 
> The radio's accessory connector pin #  11 seems to be raw audio (before
> squelch switch circuit) and it does not mimic the operation of the
> speaker.  It does not quiet and is only "Partially Programmable" which
> seems to mean that it can be set "Flat" or " Filtered" audio.
> 
> I don't want to use speaker audio for the fear of someone adjusting the
> volume control effecting the output to the consoles.
> 
> Does anyone know how to overcome this?
> 
> Bill Morphy
> [email protected]
> 
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