It "used" to break down like this...
First number is the Shift...ie
1= Night shift or graveyard
2= Day shift
3= Evenings or swing shift
Next is the letter...( the particular area of the county based on 4 areas of operation)
King = metro unit Area 2
Lincoln = Metro units area 2
Nora=Riverdale Area 3
Paul = Mendota Area 1
?? = Shaver Lake units Area 4
?? = Dunlap/ Squaw Valley Area 4
Next number is the beat within the area...
And last number is how many officers in the patrol vehicle ie..
1 = single officer or one man car
2= two officers or two man car
3= extra car
So, 2Paul31 would be day shift, Area1, Mendota area, Beat 3, one officer car.
I don't remember all the letter designations for all the patrol areas/civil/detectives etc. But the letter designates the specific assignment
It's been a long time ago and some of the designations have changed. but this is how it used to break down.