One of the key features of our new P25 trunk system is the possibility for interoperability. Every user/radio on the system can communicate with each other (if need be) through any one of the 8 mutual aid channels (or the 2 systemwide common channels which are shared with New Brunswick and Nova Scotia). For emergency personnel, these need to be assigned to you by dispatch (Medacom) in case they are currently in use by another user.
Examples of interoperability:
- RCMP, EMS and a fire department are all responding to the same motor vehicle accident. Dispatch may have all the responding units turn to the same channel (in this case we will say Mutual Aid 7) so each responding unit does not tie up a voice channel on the tower they are currently using. This would give any other users on the same tower a busy signal on their radio if all the voice channels are currently in use. All users being on the same channel only ties up 1 voice channel.
- A fire department is on a call far away from their station and is having issues communicating on their VHF radio back to the fire hall (or vice versa). They can ask dispatch to assign them an operations talkgroup. They are similar to mutual aid talkgroups, but are specifically designated for fire operations. Our system has 3 operations talkgroups assigned to each county. RVF West, RVF Central, and RVF East. Fire departments should not communicate on the dispatch talkgroup (RVF Dispatch) as it may tie up the channel preventing another department to communicate with dispatch.
Mutual Aid channels are kept “in the clear” so users who do not use encryption can communicate with those who do. A prime example of this is when fire departments need to communicate with EMS or RCMP, who both use encryption. Dispatch will either assign them a mutual aid channel or a Medical First Responders (MFR) channel.
That is a quick rundown of how interoperability works.