Being a retired JCFD officer I can help you here. So, JCFD doesn't have an E3, but they do have a Ladder 3. When JC has a fire, mutual aid relocating into JC firehouses to cover the city will have a tool box with things they will need in JC and there is dedicated radios for relocating companies. Companies going to a fire, ( it would be a forth alarm, unless there is other fires then MA will go to a fire sooner) so companies going to work at a fire may have the ability to go to the JCFD analog FG channels, if they don't have a radio that will work on JC FG, they will be paired with a JCC company or they will work on their own channel and have a chief at the command post to relay messages. JCFD dispatch and other TRS TG's are all P25 phase 1 ADP encryption. (Don't ask) JC also had cross band repeaters the BC would bring to an out of town fire to patch JC to the VHF of the other town. Now all JCFD members have Motorola APX 8000tri band radios so they can just switch to that towns channel. Most of the time with fires in other towns/City's, everyone will work on their own channel with a chief at the command post. We almost never switched to a UTAC channel, a few fireboat drills we used a UTAC channel. Northern NJ is terrible with radio interrogability still, even with all the new options. If two E3's were at a fire, they would say North Hudson E3 to to command or Hoboken E3 to Jersey City Fire Dispatch. I hope this helps.