Tone remote network...Comments??

[MSS-Dave]

Hi all, like to get some more learned input on this.

I have a DC Remote network spread out over 4 buildings. Uses standard Telco wiring, CPI DC Adaptors and Desktops hooked up to gasp: EDACS MDX mobiles. Works fine, has for over 15 years (but I've only been here for 5...). Wiring from the radio adaptor side goes to 66 blocks where it then cross-connects to the internal extension wiring to the desk. Over 4 buildings, there are probably 75 to 100 desksets that have access to 1 control station. I will be replacing the EDACS stuff with 800 MHz SmartZone equipment. Right now, the control station would be a XTL2500.

My question: Think I could do the same as above using existing wiring and just change out the DC equipment to Tone equipment? Is the XTL capable of a aftermarket remote adaptor like CPI or equivalent or does it have to be MC 2500? I'm thinking that I could just remove the existing radio and interface the XTL up but I really want to get rid of the DC if I can although it has been working just fine.

TIA!

Dave

[Will]

Dave,

Stick with the existing DC remotes if the new XTL only has to have one transmit command. Your existing DC remote adapter should work on the XTL.

[RKG]

I'm impressed if you've been able to parallel 75-100 DC remotes and still keep current levels within spec.

[Jim202]

I would like to know how he does it myself. With that many remotes, I am sure that more than one
has never had the termination resistor removed. That would cause problems with the audio level
and in turn cause low transmit deviation. Unless the DC termination panel has the TX audio level
cranked all the way up to compensate for the line loading.

Glad it's not my system. There has to be issues with that many remotes connected to the same
pair of wires going to just one radio.

Jim

I'm impressed if you've been able to parallel 75-100 DC remotes and still keep current levels within spec.

[RFguy]

I see that you mention "CPI DC Adaptors and Desktops hooked up to gasp: EDACS MDX mobiles", but then you say "there are probably 75 to 100 desksets that have access to 1 control station"

So how many "desktops" per DC adapter/base station?

Also, are thes all 4-wire, full duplex units? If not, you will not hear the talk permit/busy tones when transmitting.

[MSS-Dave]

Well... I over-estimated the number of desktops actually wired in. It's between 40 and 50 total. The way the blocks are wired, there could be 100...in each building. Right..... I did NOT do this, I inherited it. My plan is to pull everything out and put new equipment in. I would like to use the existing wiring so as not to reinvent things. To answer some of the other questions...

I've never actually tested end to end levels. Deskset audio is comparable to a portable on the same talkgroup.

In the past 5 years, I've had to replace several desktops and verified that the loop resistance is set to 5K and the existing sets are the same.

The 40-50 number would be for desktops going to 1 adaptor / 1 radio. The CPI DR10 has a option to hear trunking status tone over 2 wire. The adaptor is a CPI DTP1.

I'm still thinking about just wiring the XTL to the adaptor and giving it a try. What I don't know is if the XTL has a simular accessory jack like the Radius/Maxtrac/MCS2K or if I have to graft something internal. I don't even have the radios yet but I need to be ready to move forward when it comes down.

Thanks

Dave

[Jim202]

The answer to your question is yes there is an accessory jack on the XTL low and mid power mobiles.
It is a 26 pin connector with an odd shape to it.

Motorola part number for the accessory connector is HLN6863A. You will also need to order the
extra pins # 3980034F01 to go with the connector.

You have a fixed RX audio output on pin 21. This has a DC bias on it so you will need to cap couple it.

There is PTT on pin 16. Pulling this to ground will key the TX.

On pin 23 is the "AUX MIC" connection. Again there is a DC bias on this pin so you will need a cap.

Audio ground is pin 14. Don't forget to tie pin 15, emergency to pin 14.

Now the fun part. Depending on the firmware revision in the radio, you will need to set some
software options in the radio. In the "RADIO WIDE" tab, there is an "ADVANCED" tab. In there
you will see a "PTT AUDIO SOURCE" near the bottom. This will need to be set on a trial basis. It
is the selection that has been flip flopping with the revision version. The choices are "AUX_MIC" or
"AUX_TX". If you get no audio on one selection, go to the other. I can't control the dumb
software engineers at Motorola.

The other step you might have to do is the TX audio level setting. If the TX audio is low, you
have an option of changing the TX audio gain. You do this by going into the "TX AUDIO CONTROL
PER MODE" tab selection. About mid way down on the screen you will see the "EXTERNAL MIC"
selection. More than likely you will have to set those gains to a +6 or a +9 db gain setting.
Use the mode selection on the right hand side to increase the gain. Do not use the AGC setting.

Jim

Well...

I'm still thinking about just wiring the XTL to the adaptor and giving it a try. What I don't know is if the XTL has a simular accessory jack like the Radius/Maxtrac/MCS2K or if I have to graft something internal. I don't even have the radios yet but I need to be ready to move forward when it comes down.

Thanks

Dave

[MSS-Dave]

Thanks Jim!!!!

Obviously, you have spent a lot of time getting this to work in your applications, I appreciate your sharing the info.

Dave

[chartofmaryland]

Smartzone and no channel changing ?

Wow, and here I thought all of that channel capacity goes to waste. . . .

The interfacing will go smoothly to the CPI, I have done 6 so far, all tone but the wiring is the same, and all work as they should.

Use a quality shielded cable like a leftover chunk of David Clark headset cable or any other with a shield and a drain.

The David Clark cable fits just about perfect into the side hole on the DB-26 adapter.

CoM