The "iCall" (Travelers) talkgroup was the first conceived in September of 2015 in an effort to address the problems of traveling DMR hams to be able to (seamlessly) make contact back home to their local repeater(s).  The current international talkgroups are generally language specific and/or on PTT.  This does not provide the ability to be able to "phone home" or an effective hailing talkgroup for travelers, tourists or hams in general wherever they are located in the world.  With the availability of a true hailing talkgroup, even those in the same country can use the TG to make contact back to their home repeater and then the participants can switch to TAC 310, 311, 312, etc. in the USA, TAC 1 or other PTT talkgroups that they may have in common around the world.  Obviously, the key is the hailing talkgroup first, then the alternative PTT talkgroup to switch to for the conversation.

At this time, the closest international option already in place, is TAC 1, which is PTT on most or all c-Bridges.  What is lacking is the full time hailing channel.  iCall would address that key issue.  Once contact has been made on iCall, hams should switch to TAC 1 or other appropriate talkgroup to continue their conversation with no additional impact to all the iCall repeaters which have adopted this service for the benefit of all DMR hams.  For this talkgroup to work effectively for everyone and to minimize the disruption to the repeaters supporting iCall, this should be used as a hailing talkgroup ONLY, then conversations can move to TAC 1.  This policy is already in effect on many wide area talkgroups as TAC 310 has shown.  In effect, iCall and TAC 1 will operate as a talkgroup pair, so both will be needed on participating networks and their repeater managers.

Included below is that that Email proposal.  At this time, the concept has met with little support among the independent c-Bridge operators (ICBO's).  But then TAC 310 was greeted with active hostility before and after it's introduction but ultimately has become one the the most useful talkgroups (now with 311 and 312).

Changes have been made to address the concerns raised by the original proposal.  Those changes hopefully will bring forward more c-Bridges to adopt the proposal.  If it does not work for your c-Bridge or your managers, then go PTT or dump it.  But why not give the proposal a chance to work?  Remember TAC 310 had a huge hurtle being adopted but it succeeded over the course of several years.  This idea is not designed to benefit the adopters generally but more the wider DMR community.  Maybe that is the problem; few want to (proactively) better the environment for the larger DMR group, unless there is something in it for them, directly and immediately.  I choose not to have that myopic view and am willing to foster something that holds promise to many over the few.

The initial and primary concerns appear to center around adopting this TG as a full time talkgroup with less to no opposition voiced against the concept if the talkgroup is carried as PTT.  But PTT undermines the usefulness and TAC 1 is already adopted for PTT International, any language.  So more work on the FT/PTT aspect will need to be pursued to assuage the community concerns.  The concern seems to be primarily that of a negative traffic impact locally and dismissing or ignoring the positive benefits  more generally.  The concerns can be addressed and mitigated, hopefully to the point that c-Bridge admins (and their repeater owners) would be willing to try it and provide input on any further needed mitigation.

CURRENT STATE:

• TG is for hailing only, conversations are to move to TAC 1 immediately (or other talkgroup in common between the parties).  International use would be common but some hailing within the USA is possible if no other talkgroups are available

• The iCall Talkgroup ID is: 8952  (TAC 1 is 8951)

• The CC is 93 available from: icbo-2 and the secondary server is pending until service is provided  by a TG server  (minimum of 5 c-Bridges must carry iCall before it can move to a talkgroup server)

• Suggested iCall settings are full time for all repeaters, either TS is fine

  • Ideally, iCall and TAC 1 (TAC 310, TAC 311, TAC 312, etc) should be on the same timeslot

    •  This would assure that TAC 1 is available if iCall hailing was successful, but optional

  • Use a very short hold-off timer of 1 minute for iCall to further limit potential misuse or longer conversations on the hailing talkgroup

    • Creative use of priority and "and" logic in Super Groups will further lessen misuse

  • All repeater may use an overnight mode for PTT local time if that will address concerns

  • Short talk timers may be used for easy break-in/turn off by local users not in the conversation

    • Remember:  use the non-default 1000 millisecond "Group Call Hang Timer" in your repeaters

  • Other mitigation options as desired to increase acceptance/adoption of TG

  • Remind users to move to TAC 1 (or other PTT TG) if they seem to be unaware of this need to switch

  ...more to follow as it develops