Error 601- the port handle is invalid
Solution
  1. Go into control panel > Modems > Diagnostics
  2. Highlight com port modem is located on
  3. Click on more info
  4. If you get a response from the modem then reboot
  5. If you still get the same problem > Remove modem > Restart computer > Re-install modem.
  6. still getting the problem then > check to see if RNAAPP is in memory > press CTRL ALT DEL > Highlight RNAAPP > click on end task
  7. Now reboot computer > try connecting again > if connection fails, advise customer to speak to vendor.