I had similar problems a few days but with RS-485.
From my personal experience, first, check you already have enough 5VDC. I found it was better to supply the MAX (in my case) from Arduino 5VDC.
In your case you do not have to deal with Caps and Resistors since I suspect they are all already installed in the card. Saves a lot of time.
Do you have an schematic how are you connecting from Arduino to your transceiver?
Also, in my case, my program started:
#define rxPin 2
#define txPin 3
#define rxEnable 13
#define txEnable 4
SoftwareSerial ceSerial(rxPin, txPin); // RX, TX
That new library gives you the chance to define any digital to transmit or receive. Mega has plenty.
In my case, I wrote in the setup() stage next lines to tell my Arduino how the pins will behave. Remember some are outputs (TX)
and other should act like input (RX)
I think it is evident why this configuration.
I found the next pinout but I am not sure if it is correct or nothttp://sodoityourself.com/max232-serial-level-converter/
Please double check.
If it is correct -the pinout-, you have to connect TTL pin11 and pin12 respectively to the Digital pins in your Mega Board.
After all these, remember serial speed must match exactly both sides, ie your Mega and the Hyperterminal. From my experience, the
above code produces 9600,N,8,1 but you can select from wide ranges up to 115,200.