How does the setting Detect Out of Range work when enabled?

Version 3

    Verified Product Versions

    Terminal Emulation 7.3


    1. How is TelnetCE gathering the status of the interface in order to report a problem?


    2. Is the status of the interface/signal polled or is the event triggered?


    3. If polled, what's the interval?


    4. What's the expected behavior if the poll happens simultaneous to an AP roam?


    5. We've noticed the error message lasts about 10 seconds with end users. Is this the minimum display time? Can this be configured to be shorter if the interruption is shorter?



    1. The TelnetCE application gathers information from the Wi-Fi interface by using the NDISUIO driver or its own protocol driver that provides an NDISUIO type functionality. The information comes from the Wi-Fi driver itself and can vary slightly depending on the driver's implementation. Association status is determined by querying the BSSID (OID_802_11_BSSID), if the BSSID is a valid MAC address then the device is considered associated by TelnetCE. Signal quality is determined by querying the RSSI (OID_802_11_RSSI). The RSSI returned is adjusted to a percentage by this formula: quality=(rssi+90)*2. The quality percent is then adjusted to be between 0 and 100. So 0 percent is equivalent to -90db or lower, and 100 percent is equivalent to -40db or higher. When using the Detect Signal Quality option, the out-of-range condition will also be triggered when the signal quality falls below the configured value.

    2. The TelnetCE application polls the BSSID and RSSI.

    3. The association status is queried every 500 milliseconds (.5 seconds). The signal quality is also queried every 500 milliseconds (.5 seconds).

    4. If a query happens during an AP roam then results will vary depending on what is returned by the Wi-Fi driver when roaming. Generally we do not see out-of-range conditions during roam events.

    5. The TenetCE application does not have a minimum time to display the out-of-range message. It is displayed as long as the Wi-Fi driver reports unfavorable conditions. The longest the message should be prolonged would be near the polling time of 500 milliseconds.


    Additional Information:

    *If coverage conditions are always good in the facility it may be best to disable out-of-range checking, and allow the TCP retries to handle any lost network packets. * Updating the Wi-Fi radio drivers and AP firmwares can help eliminate roaming problems. * Some Wireless APs or Wireless switches may have more optimal settings then the default. * Complicated Wi-Fi authentication and security protocols can add to roaming problems.


    Applicable Product Version(s): 7.x