Well.. here's a start. I haven't had a contact within UPD for a few years so some of this is probably outdated but here's what I can think of off the top of my head:
Charlie units are West Side on Oquirrh TG.
Juliet = Jail/Transportation usually on Req 1 TG.
Sierra = Court Security on Special Services and Matheson Courthouse TGs.
Lima = Crime Scene Investigators.
Tac = SWAT/Special Ops
Taylorsville PD:
Motor: Motorcycle
Tango = Traffic
Delta = Detectives
Shift supervisor.callsigns use a number preceeding the area identifier such as 2 Midvale or 2 Charlie. Obviously, the lower the number, the higher the rank.
If memory serves (not so much lately) numbered units go something like this.
1-99 Admin, Supervisors, Shift Sgt, etc.
100-299 = Investigators, Detectives, etc.
300-399 = Court Security
4xx = Animal Control
6xx = Canyon Units.
9xx = Search & Rescue
In the past, Alpha units were East Side, Bravo were South (Riverton, Bluffdale, etc.) Charlie units have always been West Side. I don't remember if the SO ever used Delta callsigns for Detectives. That all changed with the creation of cities within former unincorporated areas of the County (Holladay City, Cottonwood Heights, etc.) and with Taylorsville using UPD Dispatch.
Anyone with updated info please feel free to add or correct.