Digi International WR21 with 2G capable modem reboot issue

Dear Valued Digi Customer,
 
Certain models of Digi WR21 router operating in 2G mode under certain conditions may experience reboots or continually occurring reboots in the field.
 
Not all WR21s with a 2G capable modem will experience the problem. It will be based on different factors such as:
  • Power supply used
  • Distance to the cell tower (signal strength)
  • Frequency Band
  • Carrier/SIM card
  • Date of manufacture
 
WR21s with a 2G capable modem that only connect in LTE mode or that are configured to use LTE\4G as the preferred system should not be subject to the issue.
 
Affected device identification

The problem will only occur if 2G mode is being used. For example, if there is no 2G coverage at the WR21’s location or the WR21 never connects in 2G mode the problem  will not occur.
 
Potentially affected WR21s shipped between May 2020 and January 2021 and are identified with hardware revision 1209a.

 
modeltype.PNG

The hardware revision can also be found via the web interface under Administration > System Information
wr21_sysinfo.PNG

Alternatively, via Command Line Interface using the HW command:
hw
Serial Number: 337788
HW Rev: 1209a
MAC 0: 00:00:00:00:00:00
Model: WR21
Part#: WR21-UX2B-DE1-XX
RAM: 128 MB
OK
 
 The following Digi part numbers could be affected:
  • WR21-M72B-DE1-SB
  • WR21-M72B-D40-SF
  • WR21-M72A-DE1-TB
  • WR21-M22B-DE1-SB
  • WR21-U92B-DE1-SB
  • WR21-U92A-DE1-TB
  • WR21-U92B-D40-SF
  • WR21-U92A-D14-SA
  • WR21-U92A-DE1-SW
Issue mitigation and workaround
Digi has identified and fixed the problem. This fix, requires a rework of the WR21 router at Digi’s North America facility.
 
Alternatively, the problem can be prevented by locking the WR21 to a radio technology other than AUTO or 2G. In order to make this change please follow the steps below.
 
  • For LTE/4G routers such as the WR21-M2 or WR21-M7
    • Via the web interface:
      • Configuration - Network > Interfaces > Mobile
      • Set “Preferred system” to 4G
      • sys4g.PNG
      • Apply and save the configuration change
    • Via the command line:
      • modemcc 0 psys 4G
      • config 0 save
 
  • For 3G routers such as the WR21-U9
    • Via the web interface:
      • Configuration - Network > Interfaces > Mobile
      • Set “Preferred system” to 3G
      • pref_3g.PNG
      • Apply and save the configuration change
    • Via the command line:
      • modemcc 0 psys 3G
      • config 0 save

Customer Action
 
If your application uses one of the WR21 SKUs listed above AND your product uses the 2G network, please contact Digi Technical Support at tech.support@digi.com to discuss the need and process to repair your product.
We encourage customers to take action quickly to avoid a product failure while using the product on a 2G capable network.
Last updated: Mar 11, 2021

Filed Under

Cellular/Transport

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