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

[Marshall Oldham]

FYI, 

 

He is not using app_rpt software with the URI, he is using the Bridgecom MV-iL hardware with a
URI to interface to his GE Mastr III

 

So he can not set CORFROM=uisbinvert in software config.

 

73 

 

Marshall 

 

From: App_rpt-users [mailto:app_rpt-users-bounces at lists.allstarlink.org] On Behalf Of
REDBUTTON_CTRL
Sent: Saturday, March 09, 2019 5:24 PM
To: app_rpt-users at lists.allstarlink.org
Subject: Re: [App_rpt-users] GE Mastr III and DMK USB-URI

 

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

 

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