User's Manual

Chapter Four Troubleshooting
Man_455U-D Rev 3.01 Page 53
Chapter Four TROUBLESHOOTING
4.1 Power-up and Normal Operation
When power is initially connected to the 455U-D module, the module will perform internal
diagnostics to check its functions. The following table details the status of the indicating LEDs
on the front panel under normal operating conditions.
LED Indicator Condition Meaning
OK Green Normal Operation
Off Power Disconnected or Battery Over-voltage
Red Low Supply voltage or Internal Module fault
Radio RX Green flash Radio receiving data
Red flash Weak radio signal
Radio TX Flash Radio Transmitting
RS232 Yellow flash† RS232 Serial Port Activity (Older version Hardware) †
Orange flash RS-232 port receiving and transmitting simultaneously
Red flash RS232 serial port transmitting data to host device
Green flash RS232 serial port receiving data from host device
RS485 Yellow flash† RS485 Serial Port Activity (Older version Hardware) †
Orange flash RS-485 port receiving and transmitting
Red flash RS485 serial port transmitting data to host device
Green flash RS485 serial port receiving data from host device
DCD Green Modem is Online and ready to send data.
Red Modem is Online but Currently in Command Mode
Off Communications failure or data connection not established
† Hardware version 1.5 and later has extended LED functionality, providing red & green
indication on the serial LEDs. Earlier hardware support single-color (yellow) serial LEDs.
Check hardware version using ATI5 command.