NYSP Troop T Identifiers

[thinktactics 0]

Morning!

 

I've been listening in on the Thruway A channel for NYSP Troop T, Zone 1 lately, and most of the 7-series units (which sound like State Police units) identify with four-digit IDs, normally in the format  71xx. However, when I look at Zone 1 vehicles for the blue number under the right headlight, they don't follow this 71xx pattern. Instead, they show 7xx. 

 

Can anyone clarify what the vehicle numbers mean, what the radio IDs mean, and how (if at all) they are related? Cheers.