Motorola CDM-1250 PL tone control

[1585hp]

Does anyone know if you can control the Motorola CDM's internal PL tone encoder via an external logic source?

I have a pair of CDM-1250's we're wanting to use for our ham repeater, but want to control the PL tone so it is stripped during CW ID transmissions.

Our repeater controller is an Arcom RC-210, which will send logic control signals to determine when a PL tone is generated or not. I would like to use the internal CDM generator and simply control it if possible.

If that is not an option, anyone know where I can inject the tone output from a CommSpec SS-64 external tone board so that the PL tone is generated by the external encoder then injected in, say at the modulator stage?

Thanks,

James Adkins, KB0NHX

[jackhackett]

I don't have access to the manuals until tomorrow so I'm not sure about the CDM doing PL strip, but if they won't perhaps you could program a second channel with the same freq but no PL, then use external channel steering to select that channel when transmitting the ID. The only thing about that would be how it would handle someone keying up the repeater while the ID is going out.

[d119]

In the Professional Radio CPS, once you've read a codeplug, look at the following:

Radio Configuration > Accessory Pins > Accessory Package: Default

Pins 3, 6, 8, 12 and 14 can be programmed for "TX PL Inhibit (input)". This should do exactly what you want. You can program the input so that grounding it disables PL (Low), or applying +5VDC disables PL (High).

If these options are not available on the radio you are working with, check the firmware version. Current firmware for the CDM-1250 is R05.08.01. I doubt this will be an issue unless you have an EXTREMELY old radio that's never been touched, then again, it might not have ever been an issue (just speculating).

Good for you for setting up your system to strip PL on ID. Makes a system much nicer to listen to. Just don't be surprised when some jackoff complains that your system isn't Part 97 compliant... Then you can explain how the repeater DOES ID, it just does it stealthily. My MSF 5000 identifies without PL, and I've had a few morons try to tell me that I'm out of compliance because they never hear an ID. I tell them they just aren't listening.

I also recommend against using an external PL encoder/decoder as they don't always handle reverse-burst as nicely as the internal PL components. You should be able to set up the RC210 with your two CDM's without having to have any outboard PL equipment. If anyone is running Motorola portables on your repeater, it'll sound SWEET. I use an RC210 on another MSF 5000 and it sounds great.

Best of luck!

[1585hp]

Thanks guys for your help!

I programmed Pin 8 to do a PL / DPL Strip (input), active low. It works great, for both CW and voice ID's. The Arcom doesn't strip the PL on the initial ID's, though, only on beacons and if it ID's a minute or so after someone keys the repeater. Would be nice if it stripped the PL from the ID 100% of the time, but it's better than nothing.

Now, if only someone could hack the CDM's to go out of band. I KNOW they will, I just don't know how.

Thanks again,