getting a command from RS-232 device

Hi,

I'm new here. I looked a lot, but didn't found an existing post that I can use.

I need to write a little program that gets a command from a sensor by RS-232 and turn on the Led for a Sec.

I tried to learn the UART communication by the UART-03 example, but it didn't work. i use the HyperTerminal on the Computer, and I don't get an echo.

I connect the Rx and the Tx connectors without the jumper. I didn't connect the ground connector to anywhere. shoud I suppose to connect him? where?

I will thanks anyone who help me.

I'm using msp430f5438A controller on msp430f5438 experimenter board, and CCS 5.3