I hear this term referred to as a channel that NHP switches to. I do not believe it is a Desert Sky Talkgroup.
I do not believe it to be an EDACS NCORE Talkgroup either.
Is it a Mutual Aid 800 conv ?
Any help is appreciated.
Probably one of the 8Tac's interoperability/mutual aid channels. I've heard the Metro Air Unit use 8Tac91 to communicate with S&R, CCFD and BLM Rangers.