In the iCap software top toolbar, click Tools | Test Serial Port. A small window will pop up. This window will show all the data that iCap receives from your captioning software according to your current connection settings (TCP/IP Socket, Software Serial, or Hardware Serial). Then, try to write some test messages in your caption software. You should these messages appear in the Test Serial Port window as a mix of letters with some blacked-out
control characters. If you do see this, then you should expect no problems when you try to write your data to the encoder. You will need to close the test window before you start writing to the encoder.
If you see nothing in the test window, or if you see data that you suspect does not match what you are writing (remember it is normal to see control codes mixed with your text!), you should check your settings in both iCap and the caption writing software.