The incoming serial data is parsed using the {v} token (sound velocity):

In Isis check that the data are being correctly parsed using the Sensors Display - Window>Status and Control>Sensors:

The highlighted window should show the data changing in real time - (it is not necessary to check the From Data radio button unless you want the waterfall display to be corrected in real time for sound velocity)
In Isis click Tools>ASCII report:

Then check Form 1 and Click Setup form 1 > OK

Check the boxes as shown below:

To open a window that confirms what data are actually being sent click Open Window
And then Configure port...

It is possible to send the data to a specific IP address or as shown to broadcast the message to all IP addresses in the subnet (255), any port number can be chosen as long as it is not in use - if a particular port doesn't work try another.