mc1000 -> L3276 -> CDM750

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dmountjoy
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mc1000 -> L3276 -> CDM750

Post by dmountjoy »

I was given an MC1000 deskset with a L3276 remote tone adapter to connect to a CDM760 radio for an EOC. I'm not familiar with the deskset or the remote adapter, or how it functions. I've connected it how the manual says, but it still doesn't seem right. Should I be able to change frequency and monitor the line from the deskset? because I can't. I did get the deskset to key up the PTT by using an internal relay in the deskset, but not sure if thats how it is supposed to function. Essentially, I'm not sure what the "tone control" is supposed to do. should the tone control control all of the functions, including the PTT and monitor, etc?
desperado
Posts: 237
Joined: Wed Jul 15, 2009 4:29 pm
What radios do you own?: Motorola

Re: mc1000 -> L3276 -> CDM750

Post by desperado »

OK, tone remote control.
First off, get something that you can listen to the output of the deskset (2 or 4 wire audio and ensure that it's a tone deskset and not a local control deskset.
You should hear a couple short beeps and then a very low constant tone coming from the deskset.
The way this all works is tone command uses various tones for command and control.
The first tone is 2175, that's the keying tone. The second tone will run from 2050 (monitor) down to 450 (channel 16) if you have a remote that supports all 16 channels. A MC 1000 dont. They made a 1 channel version and a 4 channel version. If you have 4 buttons marked F1-F4 then it's 4 channel, if not then it's single channel.
Second thing is the interface cable for the channel selection running from the tone panel (the L3276) to the radio. Look at the number of wires.
If you count 5 wires, then it's not wired for channel change, only audio and PTT. If you have most all of the 16 pin connector filled with wires, then it's probably a full cable. Next thing to check is the programming on the radio. In the Professional CPS, there is an area where you program the accessory pins on the back of the radio. Now Pin 3 is almost always PTT. The others will vary and you will need to get out the manual for the l3276 and see what the pins are running to in order to get the channels to change correctly if the radio is not programmed for channel select off the accessory connector already.

OK, now that you have established that your deskset is tone, your radio is programmed correctly you will need to verify the configuration of the L3276 and do an alignment on it. The alignment procedure is in the book, if you don't have the book, get one. The L3276 is rather complex and not having the book, you will never get it setup correctly unless you are lucky to the point that you win the lottery every time you play. Find an old audio voltmeter or an old analog meter to do the alignment with (preferably a Simpson 260 as it reads in db) If you have a sinadder or a TIMS set, either is great and will work well but a 260 will get it done in a pinch. Run the alignment and set the switches for 4 channel with monitor and set it for 4 WIRE. The 4 Wire thing is important. It makes the command at TX audio ship across one pair of wires and the RX across a seperate set. The reason this is important is that if you hit a channel with constant noise on it, you will be locked there until the noise goes away if it's configured for 2 wire. The deskset has that settingas well if it's a tone deskset. If it' will not configure to be 4 wire then it's either local or DC control and will not work with the L3276 unless it's also DC (if it's a local control one, it will not work with the L3276 at all and can be directly interfaced into the radio without any channel change abilities. Again, if it's got channel buttons it HAS to be tone or DC. A quick dirty way to tell is put your fingers across the output wires and key the remote, if it shocks the hell out of you it's DC. There isn't enough current to harm you be certainly enough voltage to hurt think sparkplug wire.

This should get you going, You will have more question, so post them here and I will help as much as I can
Keith
CET USMSS
Field Tech
What more can I say
dmountjoy
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Re: mc1000 -> L3276 -> CDM750

Post by dmountjoy »

Hi Desperado. Thanks for the reply.

So I hooked up a buttset to the TX of the deskset and hear tones when keyed and when trying to change channels. So tone deskset.

On the accessory plug into the radio there is only 5 wires. So no channel adjust, right? Not really a problem if not as we're only using one frequency, but the deskset has 4 channels, as does the radio. Also, the extra wires are there, just not plugged into the connector. If I were so inclined, could I plug them into the connector and make the channel steer work?

I'm going to try to find the equipment to do the alignment The only 4-wire setting I see for the remote adapter is for "wireline Configuration" is that the setting you're talking about?
dmountjoy
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Posts: 4
Joined: Fri Jul 12, 2013 10:55 am

Re: mc1000 -> L3276 -> CDM750

Post by dmountjoy »

Thanks for the reply.

The deskset has 4 channel buttons and the radio has 4 channel buttons but there are only 5 wires on the radio accessory plug. So that means no channel steer, right? It's not really a big deal as we're only monitoring one frequency, but if we were to upgrade in the future, could we connect the spare wires to the connector?

I also hooked up a butt set to the tx on the deskset and can hear the tones as you described. I have this all set up on my bench and have the deskset connected from the internal terminal blocks via a cat 6 cable to the accessory port of the remote adapter. Should I be using the accesory jack on the adapter, or the line in jack? The setup guide seems to be telling me to use the accessory plug, but I want to make sure.
dmountjoy
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Posts: 4
Joined: Fri Jul 12, 2013 10:55 am

Re: mc1000 -> L3276 -> CDM750

Post by dmountjoy »

Disregard the first reply, I guess. Thought it was lost, just in the queue.
desperado
Posts: 237
Joined: Wed Jul 15, 2009 4:29 pm
What radios do you own?: Motorola

Re: mc1000 -> L3276 -> CDM750

Post by desperado »

OK if only 5 wires then cable is for single channel. Connect the wires per the manual and program the radio accessory pins to enable the channel change feature.
Yes, wireline configuration alignment is what you need to do.
You will need some sort of a audio voltmeter or oscilloscope to do the alignment and an audio generator.
Keith
CET USMSS
Field Tech
What more can I say
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