[App_rpt-users] GE Mastr III and DMK USB-URI

[REDBUTTON_CTRL]

Bret, one thing to know about the URI is that the COR input line (pin 8) 
requires a signal transition to pull to ground. This is different that a 
signal that sources voltage and goes low. the URI has internal pullup 
resistors so it doesn't look for voltage change.

So what this means is if the CAS/COR out line on the Master III does not 
pull to ground when it goes low, the URI will not see a signal change. 
The URI has a dc blocking diode on its input. So it needs to see a 
signal that either goes low when the receiver is active or when it is 
inactive.

If the Master III CAS/COR is active hi then I suggest you connect the 
CAS/COR through a 47K resistor then to the base of an NPN transistor. 
Then connect the collector to pin 8 on the URI and connect the emitter 
to gorund. This will invert the CAS/COR signal and give an open 
collector that goes to ground on receiver activity.

Then in the Allstar node set the CORFROM=usbinvert.

This means the URI will be looking for a signal to ground pin 8. then 
audio will be sent through the system.

Hope this helps.

Regards,

Jon VA3RQ

On 3/9/2019 8:26 AM, Bret Taylor wrote:
> "What channel driver are you running?  This will determine what sort 
> of audio
> you need from the system and where squelch is performed."
>
> I'm using a Bridgecom MV-i1 to drive the URI - 
> https://www.bridgecomsystems.com/collections/tl-net/products/mv-1
>
> I don't know exactly what is under the hood. Their "OS" is called 
> TL-Net. But under that is Raspbian. I have a network of TRBO repeaters 
> that the MV-i1 taps into through IP Site Connect.
>
> I'm trying to bridge the TRBO repeaters to this Mastr III base 
> station. I've already created a cable using the info from 
> http://www.repeater-builder.com/ge/mastr3/m3-ctrl/m3-ctrl.html
>
> I created a bridge group in TL-Net to bridge the analog interface to 
> IPSC masters. I can PTT on a DMR programmed to the correct Call Group, 
> and hear it on a Analog radio tuned to the Mastr III frequency.  But I 
> can not hear the Analog radios return, it doesn't seem to trigger the URI.
>
> If I use pin 8 on the URI (active low) and connect it to P5-17, or 
> P5-20 (COR & CTCSS both Active High) on the Mastr III backplane, the 
> URI goes into a broadcast storm. Using any of the optional pins for 
> COR (2 & 3 both listed as active high) nothing happens. I suspect 
> since these are GPIO, the configuration (for the URI?) is incorrect.
>
> I know the URI works, as I was able to use it to drive an XPR5550e 
> programmed to the analog frequency of the Mastr III. It's just not the 
> best situation to run it like that. You clearly hear dispatch, but 
> since I'm not tapped onto the return path of the antenna connected to 
> the Mastr III, the mobiles response clarity is dependent on the 
> proximity to the antenna of the XPR5550e.
>
> "Double check your programing too, as the Mastr III IO is based on 
> programing.
>  You'll need to ensure you have your de-empahsis and pre-emphasis setup
> properly too."
>
> I do not have the Mastr III programming software (and can't seem to 
> find it anywhere). Another user in this list says he has it, but it 
> searching for it. So, I have no idea how it's programmed. It's 
> possible the backplane connecters for audio out are disabled?
>
> Thanks for your help.
> --Bret Taylor
> Olympia School District
>
>
> On Fri, Mar 8, 2019 at 7:49 PM Bryan Fields <Bryan at bryanfields.net 
> <mailto:Bryan at bryanfields.net>> wrote:
>
>     On 3/8/19 6:21 PM, Bret Taylor wrote:
>     > Has anyone successfully interfaced the DMK USB-URI to a GE Mastr III
>     > repeater/base station?
>
>     I think a few have, I've not personally done this.
>
>     > I've got transmit working correctly, but can seem to get the
>     received audio
>     > back into the device correctly.
>
>     What channel driver are you running?  This will determine what
>     sort of audio
>     you need from the system and where squelch is performed.
>
>     There is some info on this page and I suspect it will be trivial
>     to use this
>     to build a cable to interface to the Mastr III.
>     http://www.repeater-builder.com/ge/mastr3/m3-ctrl/m3-ctrl.html
>
>     Double check your programing too, as the Mastr III IO is based on
>     programing.
>      You'll need to ensure you have your de-empahsis and pre-emphasis
>     setup
>     properly too.
>
>     If you get a working config, please consider adding it to the wiki
>     or posting
>     here.
>
>     https://wiki.allstarlink.org/wiki/Radio_Connections
>
>     73's
>     -- 
>     Bryan Fields
>
>     727-409-1194 - Voice
>     http://bryanfields.net
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