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245U-E Wireless Ethernet Modem User Manual
21
Rev Version 2.24
encryption scheme is configured, the LINK LED will turn on, but data cannot be passed over the
wireless network.
How a Link Connection is Lost
The access point refreshes the link status with a client every time a message is received from that client.
If nothing is received from a client for a period of 120 seconds, the access point sends a “link-check”
message. If there is no response to the link-check, a de-authenticate message is sent and the link is
dropped.
A client monitors beacon messages from an access point to determine whether the link is still present. If
the client can no longer receive beacons from the access point it assumes that the access point is out of
range and the link is dropped. Whenever a client is not connected to an access point, it will cyclically scan
all available channels for a suitable access point.
Roaming Clients
Clients can roam within a system, but if the link to the access point fails or the radio signal level becomes
too weak it will scan for beacons and connect to an access point (provided the SSID and any encryption
methods, keys are compatible). If there are multiple access points, it will select the connection with the
best signal level. This functionality permits a client to have mobility while maintaining a link with the most
suitable access point.
LED Indication
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.
OK
Flashing Red / Green
Module boot sequence.
Radio RX
Green flash
Radio receiving data (good signal strength).
Radio RX
Red flash
Radio receiving data (low signal strength).
TX/LINK
Green
Radio connection established.
TX/LINK
Red flash
Radio transmitting.
RS-232
Green flash
Data sent from RS-232 serial port.
RS-232
Red flash
Data received to RS-232 serial port.
LAN
ON
Link established on Ethernet port
LAN
Flash
Activity on Ethernet port.
RS-485
Green flash
Data sent from RS-485 serial port.
RS-485
Red flash
Data received to RS-485 serial port.
DIO
Green
Digital input is grounded.
DIO
Red
Digital output is active.
DIO
Off
Digital output off and input is open circuit.
The Ethernet RJ45 port incorporates two indication LEDs. The Link LED comes on when there is a
connection on the Ethernet port, and will blink off briefly when activity is detected on the Ethernet port.
The 100-MB LED indicates that the connection is at 100 MBit/sec. The 100-MB LED will be off for 10 MB/
sec connection. Other conditions indicating a fault are described in “Chapter 4 - DIAGNOSTICS.”