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Master Control Talkgroups
 

Master Control Talkgroups or MCT's are special talkgroups (group calls) that will override the default or normal settings and timers of most or possibly all talkgroups on a given manager.  Up to 4 channels may be needed to control both timeslots to make use of the power of the MCT method of talkgroup control. 

NOTE: Local 1 and Local 2 will also have the same "control off" capabilities but typically for a shorter off time (typically only 5 minutes) and only on their own timeslots.  Suggest that Local 1 and Local 2 be placed in channel  positions 1 & 2 for quick and easy access if you wish to turn off other talkgroups on those respective timeslots.

Manager IPSC Network Status / Notes TS 1 On TS 1 Off TS2 On TS2 Off
03   05-06 UOVDG coded (old manager) 16771031 16770031 Use TS1 Use TS1
07   13-14 Sparks Nevada coded with several hold-offs 16771071 16770071 Use TS1 Use TS1
08   15-16 Aiken normal hold-off network also 16771151 16770151    
10   19-20 Humboldt 59/29 timers 16771191 16770191 16771202 16770202
13   25-26 Spokane partially coded but with all hold-offs 16771251 16770251 Use TS1 Use TS1
14   27-28   (not coded)        
23   45-46 PNW Talker Demonstration Project 16771451 16770451    
25   49-50 Open IPSC Network coded with many hold-offs 16771491      
29   57-58 Oregon North (not coded, normal hold-offs) 16771571 16770571 16771582 16770582
30   59-60 Capital-Olypia coded 16771591 16770591 16771602 16770602
31   61-62 Oregon South coded 16771611 16770611 Use TS1 Use TS1
32   63-64 Mt Hood OR coded 16771631 16770631 Use TS1 Use TS1
33   65-66 Mt Hebo OR coded 16771651 16770651 Use TS1 Use TS1
34   67-68 GAFS coded 16771671 16770671 Use TS1 Use TS1
35   69-70 WA Spare (not coded) 16771691 16770691 Use TS1 Use TS1
36   71-72 Rainier Hill coded  (10-5-16) 16771791 16770711 Use TS1 Use TS1
37   73-74 Omaha coded 12-31-16 16771731 16770731 Use TS1 Use TS1
41   81-82 Wrightwood coded  55/15 16771811 16770811 Use TS1 Use TS1
42   83-84 Santiago coded  55/15 16771831 16770831 Use TS1 Use TS1
43   85-86 Quartzite coded  55/15 16771851 16770851 Use TS1 Use TS1
44   87-88 (Inland) coded  55/15 16771871 16770871 Use TS1 Use TS1
45   89-90 (Inland) coded  55/15 16771891 16770891 Use TS1 Use TS1

NOTE:  ALL MCT's must TX on timeslot 1, do not TX on timeslot 2, even though the MCT may control timeslot 2 talkgroups.

Local 1 & 2 can be used as shorter MCT Off controls, so the additional MCT talkgroups may not needed in all user zones
 

How it Works

These talkgroups are special in that they are not used for voice traffic but as a control method (much like DTMF) to override the standard or default talkgroup timers and states associated with each talkgroup.  Newly created c-Bridge managers (IPSC network repeater groups) will be based on this Master Control Talkgroup (MCT) concept while older managers will keep their hold-off timers as the primary method of talkgroup manipulation.

  • Suggested:  Use One Touch buttons or place Local 1 & 2 channels either in position 1 & 2 or 15 & 16 on HT's for easy and frequent access.  One touch is best for MCT on's while MCT off's are best used in position 16 (or 15/16) on a HT for quick kerchunks.  You may wish to set the One Touch menu timer to 30's or so.

  • Each manager will have 1 set of two MCT's; "Master Off" and "Master On" for one or both timeslots.  Some larger managers will have a second set of 2 MCT's for control of timeslot 2 independently from what otherwide would be both timeslots

  • Each MCT On will turn on all networked TG's on one or both timeslots (typically 55 or 59 minutes)

  • Each MCT Off will turn off all networked TG's on one or both timeslots (typically 15 or 29 minutes)

  • Local 1 & 2 will also act as MCT Off's but with shorter hold-off timers (typically 5 minutes)

  • Some PTT talkgroups may be turned on via MCT; programming is up to repeater owner on which if any

How it will work for a DCI/PNW local repeater user:

Normally a user should turn off all talkgroups prior to making a call.  Then a kerchunk on the talkgroup of choice will turn this one talkgroup back on.  Once done with a conversation, the user should kerchunk the Master On to return their repeater(s) back to normal operation.  If they fail to do this, the default state will return within 10-20 minutes, a time span determined by the network manager and/or repeater owners.  This time span is selected to try to match the typical length of a conversation.  If a conversation is longer than the timer, then the user should re-kerchunk the Master Off or you will roll the dice on loosing the timeslot to another talkgroup that may go active.  This is the MCT method described in it's simplest form.

The stock Master On timer will turn on all talkgroups, including those that are normally full time by default just incase they were turned off.  The network manager and/or the repeater owners may select other options such all talkgroups on or some of the PTT talkgroups turned on.  This is all determined before the manager is coded.  So some or all of the PTT talkgroups could be turned on as some sort of monitoring situation.

If the user doesn't Master Off first, then any talkgroup that is fulltime is capable for grabbing the timeslot and preempting the current conversation.  The user would then need to time a Master Off kerchunk between the current talkers Tx cycle.  Then kerchunk their talkgroup back on.  If you don't mind losing your active conversation, then no need to use the MCT's.

It is suggested that users with HT's, program the Master On and Master off MCT's in positions 15 and 16 (and 13/14 if both timeslots are used in one zone).  This will make it easy to spin the dial to the top to quickly turn off the talkgroups.  Mobiles with more channels may wish to have more than 1 MCT set in the zone to simply getting to them for a kerchunk.

Another user radio programming option is to program up the MCT via dedicated front panel keys if your radio supports it so there is no need to have the MCT's using 2 or 4 channel slots in your zone.  Pushing outside the box, the MCT Off TG's could be used a Local only talkgroup on either slot, increasing the versatility of that channel slot.

Example: 

Let's say that Comm 2, Bridge 2 and Mountain 2 are all on full time (by default), this being typical for most DCI managers.  Now comes a local user who wants to talk on TAC 310 (PTT by default).  The user has two choices, key up on TAC 310 to turn it on and then begin a conversation or kerchunking "MCT 2 Off" then switching to TAC 310. 

If the local user skips the "MCT 2 Off" step, everything can still work fine but those three full time talkgroups could go busy at any time and capture the timeslot thereby taking TAC 310 away from the active local user.  This effectively ends that local users conversation when other networked talkgroups are enabled but idling.

To keep from having the rug pulled out from under the local user, the user should turn off all talkgroup by kerchunking the "MCT 2 Off" talkgroup.  This provides 29 minutes (typically) of "quiet time" for a conversation.

At the end of the local user's conversation, the MCT 2 On talkgroup should be kerchunks to turn the timeslot's talkgroups back to normal.  If that is not done, then at the end of that 29 minute period, the talkgroups would return to their default state.

So while MCT's are optional, they play an important role in for local users who wish to engage in a conversation.

PRO's:

  • Simple understanding to our local users on how the system works
  • Either talkgroups are On or Off
  • Can be called up via One Touch front panel programming via TRBO HT's and likely other makes as well
  • Fewer competing timer interactions to confuse users
  • Can be used to monitor nets (passively) without other talkgroup interruptions
  • c-Bridge admin time is minimized by a factor of up to 16 times simply to program a new manager
  • Local 1 & 2 will also act as MCT Off's but can have shorter hold-off timers of 5-15 minutes typically
  • Some c-Bridge groups are already using some form of MCT already. 
  • This admin has used MCT's for years on his local repeater managers and uses them daily

CON's:

  • Less intelligent control dynamically during and between conversations
  • User should know and remember to initiate the sequence before beginning a conversation
  • May require the use of and space for the additional 1, 2 or 4 more talkgroups for dedicated channel space in zones
  • It is a new approach and harder for existing users to embrace change

While some "automation" is lost as are 1 or 2 channels per timeslot in a subscriber radio zone (suggest using One Touch buttons), this is a huge benefit to the admin who must code in up to all 37 timeslot 2 hold-offs for each of the talkgroups on the timeslot.  At the low end, 15 talkgroups on 1 manager can be 225 hold off timers or up to 1370 timers at the high end.  MCT's require only 1 timer per talkgroup or 15 additional line entries for a minimal timeslot.  Local 1 and Local 2 will add another hold-off timer entry but still well short of the upper end of 1300 plus currently.

In practice, there will likely a dual use of Locals as well as a combination of hold off timers for the full time talkgroups added to supplement the MCT's to insure a better experience by the local repeater users.  But at this point, a new manager with 15 TG's could be created and be useable in about an hour, far less than the 6-8 hours entering all the possible hold off timer combinations.
 

Revised: 03/22/2020 09:36

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