Back in "the day", the unit call numbers for patrol officers was the first three of the patrol district (xxx) followed by an even number starting at 0 for each unit in that district (I.e., 5310, 5312, 5314, etc.). Since we've had ProVoice decoding and I've started listening to them again, I've been hearing some odd numbers as the fourth digit (5311, 5313, etc.) mixed in with the traditional even numbers. Does anyone have any inside scoop as to what the distinction is?