The Time Send family of tools provide a simple way to check if a coms link is working. This is done by just sending the time (possibly with some padding) over the comms link.
The UDP version is simple and just sends the time via UDP to the remote port
The RS-232 version supports sending data out though a com port or setting up a pipe though a receiver. Which is very useful for testing radio issues in place.
To use the pipe option, you must the set the receiver port you are connected to and the radio port. Check the Pipe Data though receiver option and the data will be piped though the receiver to the radio port.