Standard Horizon CP150 Owner's Manual page 57

If the data displayed on the screen is unrecognizable, you may have selected the wrong
input parameters for your particular receiver, for example, Baud Rate 9600 instead of
Baud Rate 4800. Check your receiver manual to be sure that you have selected the
proper parameter. If the screen is blank, you may have a broken connection, and no
data is being received or you may have connected the device to the other input port.
Use 'ZOOM IN' to stop (or continue after pause) data displaying, 'ENTER' to show data
in hex or ASCII mode (normal or small) and 'CLEAR' to exit.
GPS Chart 150 Page 59