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.
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
Each MCT On will turn
on all networked TG's on one or both timeslots (typically 55 or
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
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
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
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
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
- 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
- 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
have shorter hold-off timers of 5-15 minutes
- 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
- Less intelligent control dynamically during and
- 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