78 & 88 are in the database....but they are listed as multiple incident fire TGs....whereas 99 is listed as a Fire-Police Common TG. Yet, the fire radio bandplan shows 78, 88 & 99 as all being F-P TGs. Maybe the database needs to be updated/clarified if all are truly FD to PD in nature. Our current police database listing doesn't cite 78 or 88.....maybe these have been programmed into the police radios recently?
Dave, I heard PD using TG 78 tonight for a traffic detail in Northpoint following a fireworks display. It is the same TGID as before, I guess they just programmed it into the PD radios in addition to having it in the FD radios.
The talkaround channels "241" and "242" are simply two of the trunked frequencies, on the high side, in simplex mode; I'm not sure specifically which two. The reason I know this is because we tried to use 242 in a dead spot one day, and every time we keyed up, the radio denied the transmission and unsquelched, revealing transmissions from the trunked system.
Back in the time of the STX, PD had talk-around channels too, and they were also simplex mode of a handful of trunked channels. I don't know if the new PD radios have the talkaround channels or not.
I know I'm a dinosaur when it comes to this info, but when I used to work for BCOPD we had 78 and 88 as IAC 78 and IAC 88. We also had talkarounds TA 246 EST and TA 247 WST. The TA's were used occasionally at special events but other than that they were pretty useless. I have no idea what frequencies they were though, unfortunately. These were all programmed into the MTS2000's along with other TG patches to surrounding systems.
things are going great out here, its been a bit hot lately but thats the worst of it. Just wanted to pop into the MD forums to see whats changed since Ill be back out there for about a week. Hope that info above helped. As stale as it is, it dosnt look like Baltimore Co has changed much up with regards to their TRS.