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MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Thu Jul 17, 2008 6:31 pm
by jlemley
Hello All

I was presented with a problem on Monday one of our local police departments UHF repeater was hit by lightning and the department is in need of some new equipment. This department uses their repeater with a MRTI due to lack of cell coverage and no one at there station to answer the phone.

The old system used Inv/scramblers located in each handheld and in the repeater, to try and provide some means of security.

As we all no its public safety so funding is scarce and they don’t have the funds to go to an ASTRO type system.

I immediately thought of replacing the old system with a new MotoTrbo system due to its “some what secure” digital operation. Upon further research I was told by Motorola that the acc connector on the back of the repeater would only be active if the repeater were set up in analog mode which defeats the security purpose for going with the TRBO equipment.

My question to anyone who might be able to help me is the TRBO mobiles acc connector the same as in a CDM or Maxtrac 16 pin?? If so do they provide analog Rx and TX audio and a cor and ptt pins. If they do, would I be able to set up 2 TRBO mobiles with a RICK or use a MRTI as a controller and build my on Digital repeater like the old analog GR series? Let’s say to XPR4300s and a RICK??????

My brain say that even if the signal is digital that for my ears to hear it and for someone to say it there has to be digital to analog conversion some where, question is " is it at the Acc connector"

Thanks for any help any one can give me.

UHF 450 MHz 470 MHz range

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Fri Jul 18, 2008 12:09 am
by Tinker'r
No, the Accessory connector of the CDM is totally different than the Mototrbo Mobiles (26 Pin). Yes, there is a RX, TX, PTT, PL Detect, and ground on the Mototrbo Accessory connector. Although I can't seem to get the "PL\Talk Group Detect" Accessory pin to work in Digital Mode. They work fine in Analog.

Tinker'r

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Fri Jul 18, 2008 2:50 am
by wavetar
Correct, there is no COR at the accessory connector in digital mode. There are a couple of different points inside the radio that can potentially be used to source a COR. Myself & others have built cross-band circuits with TRBO mobiles. In your case, the signal would be "double-vocoded", meaning the RX radio will convert it to analog at the accessory connector, and the TX radio will convert that back to digital to go out over the air. TRBO audio is borderline as it is (not as good as later firmware P25 audio, IMHO) so I don't think what you'll end up with will be acceptable. Motorola is missing out on a lot of potential sales due to lack of digital accessories for the XPR8300.

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Fri Jul 18, 2008 10:53 am
by jlemley
Thanks for all your help.

Maybe the big /\/\ will be fix some of these issues in later firmware untill then I will go another route.

Thanks again !!!

Jeff

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Sun Jul 20, 2008 9:37 pm
by jlemley
Guys

Just took a look at the other post about Firmware Release 01.03.02 and 01.03.03 with CPS 3.6 which allows PL/Talk Group Dectect on the ACC connector of the repeater.

What do you think my chances are for connecting the MRTI now? or is it even worth the time ?

Do you think that there will still be audio problams? I listened to a wav file of the TRBO audio and it is kind of bad, sounds like a cheep Cell phone in a paper bag.

TIA

Jeff

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Mon Jul 21, 2008 10:03 am
by wavetar
It only enables PL/talkgroup detect for analog mode, I'm quite sure.

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Thu Oct 09, 2008 2:53 pm
by jefflanska
That is correct wavetar. You cannot connect anything to the repeater if it is digital mode and expect to transmit. This being that the repeater is not setup like a base radio (i.e. Digital ID, Talkgroup selection). You would need an interface device much like the DIU-3000 is to the quantar. I've been talking to a few companies about this issue and it sounds like Zetron will be making a phone interface that will patch into a later firmware version of the repeater to give you a controller. You're best bet would be to take the two mobiles and take your COR from your receive audio. I will be working on this in the next few weeks for a few customers going trbo digital around here. I'll try and post pinouts and whatnot at that time.

Jeff L

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Thu Oct 09, 2008 4:13 pm
by abbylind
I didnt think TRBO was recommended for Public Safety applications

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Thu Oct 09, 2008 9:03 pm
by escomm
abbylind wrote:I didnt think TRBO was recommended for Public Safety applications

it is

well it's advertised as such. don't see how you can't call that a recommendation

Re: MRTI with a TRBO repeater (Kind of Long Sorry)

Posted: Sat Oct 11, 2008 9:41 am
by SmackDaddy
Would it be possible for someone to tell us about the internal points they have used to get a digital COR signal? It would be very helpful when trying to interface mobiles to external devices.

Thanks,
SD.