PlayStation Development Network

Hi! I found some strange memory card in the dumpster a while ago.
When I start the PlayStation the display always shows "AJ" and then goes off after a few seconds.
Does anybody know what exactly this is?

Sure.
It's a multi slot Memory Card. You control it by holding Select and L1 or R1. Each slot then shows up as a single card.
Beware though that they're a little unstable. Never try to format them, or do any operations using a manager other than the PSX BIOS one. Otherwise, they tend to corrupt and take all your saves with them.

Thanks rama3! Works perfect!

I have a memory card like this but with a physical button on the memory card to switch bank.
How is it possible without a physical button ?
I don't understand how this memory card can tell the playstation to trigger something from the gamepad ?
Wouldn't it require some custom code to be injected in memory ?
If this is possible from a memory card, this mean that an hacking method is possible using a simple memory card just like the FreeMcBoot on PS2 ?

Maybe because the controller and the memory card share the same serial connection and the card listens to the controller input?

Yep, these cards just listen in on the bus

ok, I didn't know the gamepad and memory card bus was shared.
that's kind of messed up ...

Well, it's economical. The bus is fast enough to serve many peripherals, so they could save on controllers and board space + cabling.