FACT: Communication Manager 5.x SYMPTOM: Error: "635" Modem / Tethering CAUSE: This error may be reported if an unexpected error has occurred while connected to a GSM network. Go to link , it will give you the information need to get the internet working. The ACM cannot be the latest need ACM-6.9.115 for it to work


1. Validate the software indicates that wireless service is available. If it does not, troubleshoot data service availability.  
  2. If problem persist, click the cancel button and wait for Communication Manager to display, "Ready to Connect".  
  3. Close Communication Manager making sure the application shuts down completely. Verify no icon remains in the system tray.  
  4. Open Communication Manager and attempt to connect.  
  5. If Communication Manager displays "Ready to Connect" but is unable to connect, troubleshoot software conflicts and issues.  
  6. If still unable to connect and receiving error, for further assistance contact AT&T Customer Service for wireless customers.