MAX489E questions - w/ photo - Help me stick it to the man!

I have a piece of obsolete equipment that is no longer made. The company that made this thing is notoriously secret about anything technical, and there is no technical documentation available that I can find. I'm trying to make a compatible replacement of it using Arduino. The device has a "Data In" port and a "Data Out" port. Each port has 5 wires running to it, and each port has a MAX489E chip on the board. The logic on the original board is handled by a MC68HC11E1CFNE2 microcontroller, but I'll be using an Arduino instead.

The MAX489E is an RS422/RS485 chip. I need to figure out 3 things:

  1. Is it using RS422 or RS485?
  2. What baudrate is it running at?
  3. Which wires are used for power, data, etc? What's the pinout? How would I figure this out?

Once I figure out these things, I can build an RS4xx sniffer and put it on the bus to start documenting the protocol. Actually, if I figure out #3, I can probably figure out the other 2 by trial and error.

Here's a photo:

The data sheet for the MAX489 shows you which pins are which, so trace those to the port connections.

Use an oscilloscope or logic analyzer to determine the communications protocol and Baud rate.