Odd output with ASCII read

I'm getting a really weird serial read through an RS232 port to an Ardunio Mega 2560. I've connected to the (0,1) Tx Rx pins and I'm using an Ardunio to RS232 device with a MAX232 chip.

When I go to the serial window the numbers I'm trying to read, start being printed (I know they're correct as I have another terminal set up that tells me what the output from my device is) and then the set up runs and says <"Ardunio ready"> and stops printing anymore data.

The output I get from the serial window reads as follows.

0, 11.987, 0,0,37, 1[]

(NOTE: the [] is supposed to be a square.)

I'm using the code from the 3rd example from this thread Serial Input Basics - Programming Questions - Arduino Forum.

I would suggest that you connect the MAX232 to one of the other serial ports on the Mega. There are 3 besides Serial (USB). Having 2 things (MAX232 and serial monitor) connected to the same serial port often will not work.