Magnetic card reader, track 2

I have a card reader and a load of cards.
I'd like to be able to read the cards & use them for access control, as where I work they are everywhere.
As far as I can tell they use track2, but I dont know a great deal about cards, each card has a number printed on it, which we use to 'program' new cards into the system, after wiring up my reader (Spi interface) to a saleae logic analyser I get an output but I dont see the card number, so obviously its either not there or encrypted.
Any ideas on data protocols for track 2.
I'm not interested in payment cards, just access control.

Try googling for 'arduino magnetic card reader' - plenty of info out there.

You might not be using an Arduino, but there's so much Arduino based information out there it's easy to search for it, and then convert it to what you want.

There are a lot of projects & instructables, but there doesnt seem to be a lot going into the details of the card.
However I found this which a lot of the other webpages seem to be based on:
https://blog.tkjelectronics.dk/2010/02/magnetic-card-lock-with-the-arduino/
Looking at the code there doesnt seem to be any 'decoding', implying data is stored unencrypted, maybe its decimal or hex rather than ascii, doesnt say, and I spose its down to the programmer of the card.
The reader used is diffo to mine the reader on the webpage is a slot, mines a swipe, but mine has a card present signal and all the other signals are the same, so is probably compatible.

Wikipedia knows a little about it:
https://en.wikipedia.org/wiki/ISO/IEC_7813

Sussed.
I found some code on github that reads track 2.
With not a tremendous amount of work I have an operational card reading door lock, the code uses a 2 dimensional array to store cards so is simple to expand.
I did try a couple of my expired bank cards, that was interesting, but I'd better not mention that here for security & forum rules reasons.