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

C B harvard5362 at yahoo.com
Sun Mar 10 14:44:55 UTC 2019


Hi
Mastr III can be interfaced to the URI by simply using P5 pin 20 (RUS) for both Carrier and Pl detect to pin 8 of the URI
this has been working as intended for many years.
Chris

      From: REDBUTTON_CTRL <jrorke at cogeco.ca>
 To: app_rpt-users at lists.allstarlink.org 
 Sent: Saturday, March 9, 2019 5:32 PM
 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    
     
  On Fri, Mar 8, 2019 at 7:49 PM Bryan Fields <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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