Linking CDM1250 to XTL2500? (simplex to trunked)

[tmtu]

Hi Everyone,

Has anyone had experience linking a CDM1250 to a XTL2500?

I know there is an extensive pinout option on the XTL2500... just can't figure out the right combination of PTT/ground/TX/RX...

What I'd like to do:

- When the CDM1250 is RX analog voice, keyup the XTL2500 to broadcast that audio on a trunked talkgroup.
- If possible, perform the same in a vice-versa mode.

Anyone know what pinout combinations need to be used to accomplish this?

Thanks!

[d119]

Hrm... Thats a good question.

Pin 13 of the XTL 2500 rear accessory connector is CHAN ACT (Channel Activity). Assuming this goes active when the talkgroup has traffic on it, you could use it to key the CDM.

Notes on the CHAN ACT line from the basic service manual are as follows:

13 CHAN ACT Channel Activity 0-5 volt output used for indicating detection/unsquelching of a qualified received signal. As of the release of this manual only UHF R2 is APCO compliant active low.

6816532H01-B is the part number for the XTL 2500 basic service manual. You'll probably want to get your hands on it as it has the complete pinout for the rear accessory connector. Provided the CHAN ACT line actually works, everything you need should be back there (Chan Act, PTT, TxAud, RxAud).

Obviously on a CDM series radio all that is on the back connector of it, so it's just a matter of interfacing the two radios properly, and being able to adjust audio levels in between.

The only downside to this is that the user on the CDM side of the link will have to wait for the far end to unkey (if there is any repeater hang-time this will factor in), other than that it should work.

[tmtu]

Thanks for the input.

Had a look at the service manual... so many options. If I figure it out, I'll post the pinout for everybody!

[DFD565]

Did you ever figure this out.. I'm looking to do the same type of operation.

Thanks

[ai4ui]

I have an XTL5000 connected to a Quantar repeater for patching purposes in a deployable interop trailer using a nhrc-6 bidirectional repeater controller . Pin 13 on the xtl is active high on channel activity. On the quantar I am using the MRTI port for the connection. The quantar is using it's internal controller to control it's repeat activity, so the nhrc "sees" it as a simplex radio. The nhrc controller is not involved in any control functions of the quantar because we have to have the capability to run the quantar in digital/secure.

With this setup I can patch the quantar onto our trunked system, or any other radio system by using xtl's from different bands. It also provides remote DTMF setup & knockdown of the patch, as well as time-out timers.

The only real drawback is that because there is no DIU, digital traffic from the quantar does not get transmitted on the patch. However, if the xtl is on a digital system, that does get patched to the quantar. None of this is an issue in your setting.

Everything you need to make this connection is available on the rear connector of CDM1250 as well as the xtl. I have some documentation if you would like.

RG

[DFD565]

@gmail.com

[n9upw]

Looks like you need a DVRS....

http://www.motorola.com/Business/US-EN/ ... 2529_US-EN

They use two XTL's to cross band (800 digital trunked-VHF), so I don't know why a CDM wouldn't work. BTW, I've seen and used the DVRS and it's a great little unit.

DSW

[tmtu]

I've been trying to use this:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0172339302

Can't get any of the pinouts to work on the XTL2500.

ai4ui, could you share the pinouts you used?

[akardam]

Even if you did get that RICK-substitute to work, there'd be no way for the user transmitting to the CDM to know they'd got a valid channel grant on the TRS or not. I'm assuming you're not planning to use this in a production or critical-level comms environment...

[ai4ui]

tmtu,

The pin out for the rear connector that I used is:

Pin 23 Aux mic (TX Audio)
Pin 16 External PTT
Pin 21 RX filtered audio (RX Audio)
Pin 13 Chan Activity (COR-Active high)

Like akardam said, though, there is no way for the users on the remote system to know that they have received a channel grant when patched directly to a trunked system. You should use pre-PTT ID to at least force the users to wait for a second before they start talking. That will provide some delay for everything to "connect" before they start talking.

The primary purpose of our project is to tie our deployable repeater into one of the NPSPAC mutual aid repeaters which in turn is connected to the FIN (Florida Interoperability Network, aka Motobridge). Once it is connected to the FIN it can be connected to whatever participating radio resource needed at a consol level. It can be tied directly to a trunked system, but that is not without potential problems.

Good luck on your project.

Robert

[DFD565]

looking to do this in a non trunked operation(8-tac) . to allow for mutual aid interopability. we border counties with LB and VHF.. makes working with the agencies difficult with us on 800. could be useful in trunked if there was a way know they had connected.. was that pinout for the cdm or xtl?

Thanks

[ai4ui]

It's for the XTL. The CDM pinout can be found on batlabs.

RG

[tmtu]

Thanks guys.

Yep, it's just a bridge from a talkgroup to simplex channel for certain events. Nothing critical. If I get this going, I'll post my results!

[boteman]

Does the XTL5000 provide a busy indicator output on its accessory connector?

I am working on a project that could be used in this application, but primarily as a voice to IP gateway and it would be much better for trunked applications if the radio could physically tell me when it had the channel grant and was ready to open the voice channel. I saw a pin on another model labeled BUSY, but thought that was for programming not radio comms.

I can buffer several seconds of transmit audio until the radio says "GO" and that would be the bees knees. No more missed words on patched links.

Thanks!

[cguszack]

If you were to use the DVRS, going from an analog Type II system to conventional UHF, do the UHF portables get any notification of a channel grant? Basically, can the DVRS eliminate the problem akardam brought up about users not knowing whether or not a channel was granted. My department is trying to keep all communications on a UHF portable, but county dispatch is moving to 800 MHz trunked... We want to use a Quantar and interface it with a mobile radio on the trunked system, but my concern is just how well the link will actually work. All our vehicles have the appropriate mobiles, but we're trying to eliminate the need for multiple portable radios. Any thoughts/suggestions? Thanks.

[boteman]

From what I gather by reading the DVRS literature, it operates essentially as a translator, so you could use trunked portables. I don't see any other way they could have their unit ID appear on the trunked system.

For your conventional UHF application this would be overkill, yet would still not solve the root problem, precisely because the UHF side is conventional. There would be no way for the conventional users to know when to talk. So the problem persists.

[cguszack]

Okay thanks, that's how I thought it worked. It won't exactly be a critical link, just more of a convenience factor for when it's needed, so if someone gets locked out and has to repeat their message they'll live.

Thanks.

[Jim202]

One other issue that you need to know about on the XTL series mobiles is the aux mic input gain. If
your transmit audio is low, you can go into the radio software (RSS) and get into the radio wide section.
Then go to the transmit audio tab. In the middle of that page is the aux mic gain settings. Un-check
the AGC on the left and raise the gain setting box on the right to what you need. It may take a couple
of attempts to find the gain setting to match what your connecting to.

This won't cure the overall low deviation that most of the XTL radios seem to have. This is a function
of the way Motorola has chose top set the alignment up on these radios. On a VHF XTL , it seems the
max you get is about 4.0 to 4.2 KHz of deviation. If you want more, then you need to go into the
alignment software steps and set the TX deviation to a higher number than the default setting.

Another word of caution, is that there is a DC bias on this aux mic pin. You will probably need to cap
couple your connection with at least a 1.0 mf cap to keep from pulling the bias and audio down.

A good point to pull the audio from on both the CDM and the XTL radios is the fixed audio out pin.
This RX audio level will not change with the RX front panel audio level. Makes for interconnections
between pieces of equipment much easier. As with the aux mic pin, I have found it good practice to
use a cap to couple the RX audio as there is a bias on this pin as well.

Jim

[Copperlion]

Reading through all this, I have one question: what does pin21 (RX_FILT_AUDIO) use as a reference? Should it be using pin1 (digital ground), pin14 (analog ground), or some other reference? I've been trying to get clear audio from the accessory connector, independent of the volume control, to pass through a router for a remote dispatch system.
Telex would have me use the speaker +/- pins, assuming that nobody would walk by and adjust the volume on the radio once it is set up. I'd like to pass the flat, volume-independent audio to the Telex, and still have the option of a local volume-controlled speaker, if possible.

[Ideal_]

I realize this thread is getting older however I have linked an XTL2500 with a Kenwood TK-8180. The 8180 is on a conventional system and the XTL is on a 800MHz Smartzone system. I build a small controller/interface to ensure proper signalling levels and isolation were achieved. PM me if you want the schematic/notes/parts list etc. The 8180 is just a radio on a conventional repeater allowing all users to get true half duplex. You could use a CDM1550/1250/750 or even an old maxtrac or radius if need be.