OTC Wireless 802.11 Wireless Serial Solutions WiSER2400.IP - Manual (Page 30)

WiSER 2400 Technical Manual Version 2.16 Copyright  2001-2005, OTC Wireless, Inc. All Rights Reserved Page 30 of 32
A A P P P P E E N N D D I I X X
Troubleshooting
Blank Pages Appear When Opening the Administrative Program
This is possibly due to the unavailability of the COM port. Check the Connection and
Status fields at the bottom of the program’s main window. Press the Connect button
again to see if the status indicates “Connected.” If not, check to see if you have another
program running that accesses (or protects) the same COM port.
No Radio Link
If the Link Quality indicator in the Radio Status panel shows 0%, check the following for
possible causes:
• Make sure that the Signal Strength indicator under Radio Status panel is not
zero. A minimum of 20% is recommended. If the “Signal Strength” is less than
20%, the distance between the WiSER2400 and the targeted AP may be too
far. Decrease the distance between the radio pair to see if the radio link can
be improved.
• Make sure that the encryption keys are entered correctly if WEP encryption is
enabled.
• Make sure that there is no RF interference present in the radio network.
No Data Transfer While the Radio Link is Good
If the Link Quality indicator shows good link quality, but the host computer/equipment
cannot properly exchange data:
• Make sure the RS232 cables are properly connected to the radio and
computer/equipment.
• Make sure that the RS232 cables in use are not defective.
• Make sure that the COM port on the computer/equipment is available and not
used by another active program/process.
• Retrieve the “Configuration” information of the WiSER2400 by click on the
“Refresh” button. Make sure that the “IP setting” on the “Configuration” tab
are correct: IP addresses, port numbers, etc. A very clear indicator that
shows that there is a connection between the WiSER2400 radio and the
intended destination device is the “Dest unit’s MAC address” field. After
clicking the “Refresh” button a few times while the “Configuration” tab is
selected, this field should show the MAC address of the destination unit. If
this does not work, check the IP address settings.
Poor Link Quality
If the Signal Strength indicator is reasonably high (>20%) and the Link Quality is not
zero, but stays in the Poor range, it could be due to one of the following reasons:
• Make sure that radio interference is not present in the radio network.
• Make sure that the radio is not surrounded by many strongly reflecting
(metallic) surfaces. With multiple reflecting surfaces between the radio in
question and the target radio, a severe multi-path problem may introduce high
bit error rate despite a strong Signal Strength.
• Make sure that there is no severe packet collision caused by a “hidden node”
problem. A “hidden node” problem is a situation where the RF signal from two
or more Station radios cannot reach each other (but can reach the AP) (i.e.
The Bridge stations have no awareness of/cannot detect the existence of the
other station). In such situations, multiple Stations may attempt to transmit
data packet to the AP at the same time and cause packet collision. To solve
this problem, re-arrange the problematic Stations so that their RF signals are
mutually sensible to all Stations. There is no guarantee that the packet
collision can be entirely eliminated, but the severity can be reduced enough to
see visible improvement of the link quality.
Radio Interference
You may be able to minimize RF interference by doing the following:
• Although the WiSER2400, when properly configured, will seek a clear channel
to use, it cannot avoid interference if too many 2.4GHz interference sources
are present. A “clear” channel should be at least 20MHz, but preferably
30MHz, apart from any other channel in use. Find out what other usages are
in use in the vicinity and try to coordinate channel assignments with other
users.
• Reseat the WiSER2400 radio to a location where the interference is
minimized; in general, increasing the distance between radio pairs may cause
radio interference.
• Avoid using 2.4GHz cordless phone in the vicinity of the radios.
• Keep the computer with the WiSER2400 radio away from the microwave oven
and large metal objects.