With the creation of ALEA, most all state agencies with with law enforcement duties were consolidated within the new agency. The one notable exception are Conversation Officers.
The former AL Department of Public Safety consisted of Highway Patrol (Troopers) & ABI. Marine Police were taken from Conservation and merged with ALEA DPS Highway Patrol. ABI, as such, was merged with Alcohol Beverage Control (ABC) agents and became a separate arm of ALEA called the State Bureau of Investigation (SBI).
To the question at hand; marine patrol (not police now) use standard trooper call signs as does most any other absorbed agencies. The only difference, I think, is that MP unit numbers begin with the troop letter plus three numbers beginning with "6." I might be wrong about that. As far as other state agencies, there aren't any other than Conservation Officers with law enforcement officers. Well, Alabama Forestry Commission probably have a few but I think they even have some affiliation with ALEA. Revenue Agents and Public Service Commission Officers and agencies such as Agriculture & Industries cattle theft agents, etc. got swallowed by ALEA. Before that, they did have specific call signs the State Trooper radio network.
Former colleagues tell me that SBI agents seldom contact Highway Patrol Posts via VHF radio. When they do, I wager that they will ID as "SBI" followed by one to three numbers depending on how important the agent thinks they are. In fact, locally SBI doesn't have a presence in the Sate Trooper Post like the ABI did.
If SBI has any assigned frequencies other than those for the Highway Patrol Division, they would be most likely mobiles only and come from
this FCC License. (Notice the four frequencies designated as NXDN, 8K10F1E.)
With the exception of the two no longer used low band frequencies (left over from the Surface Mining Commission days), I keep the other 28 (includes state net & 2 interop V-Laws) programmed at all times at home and while travelling in Alabama. Of course those 28 also include the five DPS legacy frequencies plus two newer "splinter" frequencies assigned to Highway Posts across the state. The other frequencies are well worth exploring in my opinion.
