[Motorola] CDM750 accessory connector/ RX audio

Sun, 10 Nov 2002 14:55:40 -0500

Eric and Randy, 

I am indeed using a Motorola Tone Adapter. The audio at Pin # 11  IS 
discriminator audio which is ahead of the squelch circuits.  Pin # 11 
outputs constant noise on - no RF signal,  and audio when RF signal is
present regardless as to whether the RF signal contains the proper PL or
not.

I haven't tried setting the audio output to "Filtered",  but from the
description in the Help files, only provides a constant audio level when
set, does it not?

I am going to try just what Eric describes in using Pin#4 set to "Detect
PL/CSQ Output" and picking up an external relay to turn ON / OFF the
audio from Pin #11 when proper PL is present,  AND to do the same from 
"PL Monitor Output" from the adapter on it's Pin # 7.

It seems that there should be a better way of doing this than having to
add an external relay !

The adapter performs no PL logic from the radio's RX audio. It only
functions to switch the radio into or out of PL as commanded by the
consoles.

On Sun, 10 Nov 2002 09:17:09 -0800 Eric Lemmon <[email protected]>
writes:
> 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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Bill Morphy
[email protected]

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