This page has instructions for building your own serial cable that connects directly to the PS2’s EE processor. It only needs 5 wires soldered onto the PS2 mainboard, and a simple interface circuit to convert the EE’s voltage levels to the standard RS232 levels.
Because there are at least 10 major PS2 mainboard revsions, and I built my cable on a V4, there might a few differences in the location of the points you’ll need to solder. The main one is the pad for +3.3V. Refer to the installation diagrams of any recent modchip (Messiah, DMS, whatever) for your PS2 version, and you should be able to find the right +3.3V pad to use. Also, my pictures of the serial pads beneath the EE might differ slightly from what you see on your mainboard. As far as I know, the serial port pads exist on all PS2s, so as long as you find the right set of pads you should be fine.I used the following color scheme for the wires on the PS2 mainboard and the interface circuit:
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Red – +3.3V
Black – GND
White – EE core voltage (Vcore)
Blue – EE_TXD / PC_TXD
Green – EE_RXD / PC_RXD
First, open your PS2 and get to the mainboard. Again, use the installation instructions of a modchip to figure out how to take apart your PS2. You should be facing the side of the mainboard opposite the EE, with the A/V and optical connectors closest to you.Start by connecting GND, then locate your board’s pad for +3.3V and connect it.
If you look at the right side of the bottom of the EE, you should see 4 square-shaped pads. You should also see a gap between the first pad and the bottom three. This is the EE’s serial port. The top pad is EE_TXD. Make note of the via (the tiny circle) sitting by itself immediately above EE_TXD. That’s the EE_RXD pin. The third and fourth pads are RTS and CTS, but we won’t be using those for our cable.
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