I suppose you mean the police 10-codes. Like "10-4" and such. Those actually vary from state to state, city to city. Perhaps this thread will reveal members' favorite links to the many established (and detailed) databases on the web.
In Sacramento they use 10 codes and 9 codes. They also use state penal and vehicle codes that are not the same from state to state. In Las Vegas, they use a 4 code that I have never seen anywhere on the planet!
It is always great to share information but in this case, I don't think it would be useful.
Radio Shack sells a "Police Call" directory that is pretty trustworthy. It even comes with a CD ROM so you can make a frequency list for your area and print it out.
If you mean the "10- codes", there is no universal standard; those codes are developed by the department that uses them. The only widespread set of "universal" codes are the ones used by CB'ers. Often, the police and fire departments will use some of them and then add their own to the mix. Some departments will use statute numbers as an unofficial code for a prticular offense (3731 is the statute against drunk driving in Pennsylvania and some departments use it to indicate DUI). When the officers deviate from the department standards (which is pretty common, there used to be a chief around here that used an old set of codes that had been phased out 10 years before), your only clue is context.
While I don't promote any involvement in possible illegal activity, here's a few interesting notes on scanners.
Know anyone in either Asia or Europe? Have them bring you back (or ship you back) a scanner. The ones sold in some parts of those regions have a much better frequency range. Just two minor problems to deal with: One has to know the language in order to properly program it, and then there's the different power supply issue.
It doesn't take much of an electronics knowledge and/or knowledge in certian types of computing to know how to advance the frequency range of models sold here.
With the increased frequency range it's possible to pick up on more different types of wireless home phone conversations, even if done eerrr accidently. I've personally seen models which are capable of picking up almost any digital mobile phone conversation; but I may have been across the border while eerrr witnessing this.
The two best types of places to buy scanners are either boating stores or places which sell to private/commercial pilots; such as Sporty's Pilot Shop.
They don't have better frequency range, they just have the cellular bands unblocked. Why you want to listen to analog cell phone calls is beyond me.
How did you pick up digital mobile phone conversation I'm curious? Well, you COULD.. you'd just be hearing digital noise, because you have no way of decoding the stream? Not to mention phones that use spread-spectrum techniques and frequency-hopping that'll keep you from listening to any full conversation.
When new scanners go through the FCC, the only way they can be certified is if they cannot be modified through any simple means (jumpers/firmware, etc.) to open up the cellular band. Older scanners are known to have very simple modifications.
I'd second the call for checking out RadioReference.com.
Decoding the stream is very easy. Why does one think the cell phone hardware is so inexpensive. As for the spread spectrum and the frequency hopping, it's just another toy gadget which is also not hard to defeat.
You have to look at it this way: If it's an inexpensive piece of harware which someone had to program, then how much efort could it possibly take to decode?
One can find the books to know exactly how to do it at any good bookstore or library. If you've done any entry level electronics, entry level programming, etc. then you're probably overqualified to do it.