User's Manual
455U-D Radio Modem Module User Manual
Page 54 © Jan 2008
4.2 LED indication Diagnostics Chart
INDICATOR CONDITION MEANING
OK LED OFF Continuously
• Power supply failure
• Battery Supply Overvoltage
OK LED RED Briefly
• Module Out of buffer memory (Host device ignores
CTS)
• Low Supply Current during transmit (Modem resets)
OK LED RED Continuously –
from startup
• CPU Failure
• Radio module fault.
• Low Supply Voltage (< 7V)
• Corrupted Configuration file
OK LED RED Turns red after
startup
• CPU Failure
• Low Supply Voltage (< 7V)
OK LED FLASHING Flashes
red/green twice
per second
• Low Supply Voltage (< 10.7V)
• Modem is in low power mode – DTR control.
OK LED GREEN Continuously
• Normal Operation
Radio TX LED ON Flashes briefly
• Radio transmitting
Radio RX LED GREEN flashes
• Radio receiving data
Radio RX LED RED flash
• Radio Receiving data - Weak radio signal
Baud Setting Signal Strength
B0 Less than -111 dBm
B1 Less than -108 dBm
B2 Less than -105 dBm
B3 Less than -100 dBm
RS232 LED ON 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
Orange flash† RS232 Serial Port Activity (Older version Hardware) †
RS485 LED ON 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