How do the SGC address codes work?

Question

In Stargate SG1, Samantha Carter and the technical staff implemented their own dialling software and with it a proprietary addressing system for milky-way gates. Instead of the difficult to spell constellation-based codes used by the gate builders, it uses an alphanumeric code of the form: P3X-984. This doesn't seem to be an internal id that is just handed out whenever a new planet is visited but rather to somehow correlate with the real gate address.

To my knowledge, this code code starts with a P and typically follows the form PNL-NNN where N are any number fro 0 to 9 and L is any letter A to Z. This encoding would allow for only 260,000 addresses.

If we are generous and say the first three characters can be anything, we still end up with a mere 46,656,000 addresses. However, there are 1,987,690,320 addresses (42 times as many). Not all of these make sense as they would not describe an intersection in space, though.

How do the computer generated addresses used by Stargate Command and the humans of the Tau'ri work and how do they map to raw gate addresses?

Answer 1

Ultimately about the only thing I can find is Season 1 Episode 5 "The Broca Divide"

HAMMOND In one hour, you will go through the Gate to the planet represented by these symbols. It has been designated P3X-797.

DANIEL Couldn't we call this planet something that's a little easier to remember?

CARTER Ah, it's based on a binary code the computer uses for extrapolation.

As far as canon that is pretty much it

Answer 2

With a 6 digit code comprised of 38 unique symbols, the Stargate network in the Milky Way has: (38×37×36×35×34×33) = 1,987,690,320 possible addresses. However, not all of those possible addresses are functional, meaning either a gate with that address was buried, destroyed, or never built in the first place.

Stargate Command's planet designations have very little to do with that despite the fact that Carter once utters the ridiculous line that the designations are based on a binary interpretation, blah blah blah. If that were true, they'd be pronouncing planet designations like Binar's from Star Trek or screeching at each other like fax machines and modems.

It would make more sense if the designation codes were merely serial numbers assigned sequentially when the gate successfully dials out to a unique address, and if that were the case, Abydos would be P3X-1. I don't believe they ever mention Stargate Command's designation of Abydos.

Personally, I would've assigned each glyph a phoneme and pronounced gate addresses phonetically. This would make it easier to remember the designations and possible to type them with a qwerty keyboard, too. Unfortunately, Sam Carter didn't consult me when she designed Stargate Command's systems.