You can start
here but I've never gotten around to adding more.
The most common information:
Commands:
$3BF, $3C0 are system background words and unimportant to you
$001-$2F7 are reserved for frequency identifiers. They are used for call grants and late entry messages. 800MHz adds some command codes to the list.
System ID:
308 x <system id>
30B x <control channel hex + $2800>
x can be 1 or 0 and their meaning isn't important at the moment.
In some large networks (i.e., OminLink) $308 will be replaced with the input ID for the control channel.
Channel grant:
-Varies based on freq band-
For 800 and 900:
308 1 <radio ID>
<channel> 1 <talkgroup+ statusbit>
This will be sent four times and then the late entry OSW is sent continuously until the transmission is over. It mirrors the second word in the above dual OSW.
The command $308 is meant to mean the OSW following it is attached making a dual-OSW. There are also triple-word OSW's used in SmartZone networks.
$308 paired with $310 is an affiliation message. These will be very frequent on large, busy networks.
$308 paired with $30B is meant to mean an extended function and has a more complicated structure; most often signified a Deaffiliation. Unimportant for scanners.
PM me if you want more info as the topic can be very lengthy.
