Mitsubishi Melsec A1SJH cpu

Hi all,
Im a beginner a programming PLC's, so if anyone help with some of my questions, that would be highly appreciated.
Currently I'm working with a Mitsubishi Melsec A1SJH cpu PLC and am trying to establish communication via an RS232 to ethernet converter. However, I'm not sure about how to setup the communication with the PLC. Seeing as there isn't any ethernet module on the PLC, I'm guessing that there needs to be a ethernet to Melsec communication protocol conversion before establishing communication, and if I'm not mistaken, the communication protocol used by Mitsubishi is the Melsec Communication Protocol.

Not Ethernet. You need a SC09 cable.
Buy one here.

I do have a SC-09 cable connected to the PLC which is connected the PLC, then a RS232 from the other end of the SC-09 cable into the serial to ethernet converter box. The ethernet cable is only connected from the converter box to my PC. I'm wondering whether the Mitsubishi Melsec A1SJHCPU PLC requires more pins of the RS232(Apart from TS,RX,GND).

I normally use a serial-to-usb converter with my sc-09 cable, never had any issues. I suggest you buy one, it is cheap anyway.

I've tried that and it yes it does work. However, what I'm trying to do is use that converter box as a serial server and use it to monitor data from the PLC via Kepware.

The SC-09 cable is mainly use to upload/ download PLC program only. If you need to monitor PLC data via kepware you need to buy an ethernet module for your PLC, and do some programming. The programming instruction is usually on the programming manual.