Can I connect 2 micro controllers?

I have a PIC 2 PLUS Demo board. I am using C language and embedding it on the microcontroller. Now I have a AL5A robotic arm. The robotic arm has servo motors that need to be connected to the servo-motor-controllers on the SSC-32 micro controller board provided by Lynx Motions.

Can I connect the two boards together using a Male-to-male serial adapter and send the code from the computer to the PIC 2 Plus Demo board to the SSC-32 micro controller board?

I'm not sure what cable you have (there are a few out there and they all look the same).

You need to make sure you have the right DB-9 serial cable. You need a Null Modem cable, not an extension cable.THe difference is that the TX/RX pins either run straight through from one connector to the next, or they swap along the way.

Extension Cable:
Side A<->Side B
TX (Pin 3)<->TX (Pin 3)
RX (Pin 3)<->RX (Pin 3)

Null Modem Cable:
Side A<->Side B
TX(Pin 3)<->RX(Pin 2)
RX(Pin 2)<->TX (Pin 3)

So obviously the extension cable isn't going to work since you want to transmitted signals to end up on the receive pin. I reason that you have the wrong cable though because you say you would need a male-to-male adapter. It makes more sense for null modem cables have the same connector on both ends because they connect two computers (ie. two devices with the same connector gender) together. The same reasoning says that it makes more sense for extension cables to have different ends since they are supposed to connect end to end without changing the connector gender at the ends.So if you need a male-to-male adapter it's probably an extension cable rather than a null modem cable. I could be wrong though. You can use an ohmeter to check.
https://www.lammertbies.nl/comm/cable/RS-232.html

Thanks you very much. It helped.