This is a compilation of information from a few other sites. This information is provided solely for educational purposes, and with no guarantee of accuracy.

Disposition Codes

You’ll often hear officers call in, “You can give me a 14 Paul” or whatnot. These are known as “Miscel” codes, short for “Miscellaneous” and pronounced “missile.” The first part is the number, the second is a letter. Here’s the breakdown…

And then the latter half, the letters:

Additional Codes & Abbreviations

Some additional codes are used; they’re usually easy to remember because they’re simply abbreviations. In most cases, they’re given phonetically (e.g., “Ocean Nora” instead of “O-N”)
ON - On the air / In service
OF - Off the air / Signing off
DK - Intoxicated (drunk): usually not phonetic
CR - Clear
AR - Arriving on scene
L20 - Out of the car, longer than 20 minutes
R - As in, “Clear with an R.” Short for “report”
FIO - Field investigation; essentially a “stop and identify” type thing
209A - A relatively obscure reference to Chapter 209A of the Massachusetts General Laws, usually used to refer to protective restraining orders.
94C - A similar reference to MGL, Chapter 94C, concerning controlled substances. In practice, “94C” is almost always used to reference marijuana, although it can refer to any illegal drug.
Go to 7 (or 9) - A request that an officer switch to Channel 7 or Channel 9, two unit-to-unit channels.
Go up - See above: a reference to going “up” to channel 7 or 9.
Nova Base - Channel 8; charged with “info requests” such as license status and registration lookups.
ABPO - Short for “Assault and Battery on a Police Officer”
ABDW - Short for “Assault and Battery with a Deadly Weapon”
All Out - A broadcast (preceded by a long steady tone) occurring on all channels of the BPD radio system, used for announcements that need to reach multiple channels. (”All out” has a different meaning in the firefighting realm.)

Service Codes

You’ll also often hear a lot of “Code 19″ and the sort.

Unit IDs

Unit designators are usually expressed as four characters, like “Lima 211.” The first, a letter, denotes a location: each suburb has one, listed below. The second character denotes the type of unit, e.g. a wagon, 2-man unit, K9 unit, etc. The last two is a unique unit identifier.

Locations

Unit Types

External links

There are two sites in particular that are really handy: this one and this one.