Tripp Lite USA-49WG Windows Owner's Manual for USA-49WG 4-Port USB Serial Adap - Page 19

7.1.e - LED Behavior The Keyspan USB 4-Port Serial Adapter part number USA-49WG comes equipped with LED lights that report the status of the Keyspan adapter USB hardware and serial port. The following table shows all of the possible states of these LED light and what they mean: Color State Significance Red Off The Keyspan adapter is not connected or not receiving power from your computer. Red On The Keyspan adapter is connected and is receiving power from your computer. Green Off The Keyspan adapter software and hardware are working properly. (and Red light ON) The Keyspan serial port is available for use. Green On-Steady Light The Keyspan serial port is 'in use' by an application on your computer and is ready to send and receive data to and from your serial device. Green On-Blinking Rapidly The Keyspan serial port is sending and/or receiving data. 19