The Comm. Error message may appear on the Brother machine's LCD if the machine experienced a communication error while sending or receiving a fax. This type of error is generally caused by interference on the telephone line, an incorrect telephone line connection, or an alarm system or other device on the line.

1. Check the quality of the dial tone. (Click here to see how to verify a dial tone.)
   • If the dial tone quality is poor, contact your local telephone provider for further assistance.
   • If there is no dial tone click here.
   • If the dial tone is clear, go to Step 2.
2. Check the telephone cord connection.
   • If the telephone cord is plugged into any device other than the wall telephone jack—i.e., a surge protector or switching device—disconnect the cord from that device and plug it directly into the wall telephone jack for testing purposes. Removing such devices helps to determine whether the issue is related to the Brother machine or another device.
3. Try to re-send the fax.
   • If the fax is successful, the problem was caused by another device or piece of equipment on the line.
   • If your Brother machine displays the Comm. Error message again, go to Step 4.
4. Your Brother machine has a Compatibility setting that adjusts its sensitivity to interference on the telephone line by lowering the transmission speed.
   Change your Brother machine's Compatibility setting to Basic (for VoIP) by following these steps:
   1. Press (Settings).
   2. Press All Settings.
   3. Press Up or Down arrow key to display Initial Setup.
   4. Press Initial Setup.
   5. Press Up or Down arrow key to display Compatibility.
   6. Press Compatibility.
   7. Press Basic (for VoIP).
   8. Press (Home).
   If you change the Compatibility to Basic (for VoIP):

   • The machine will print all received faxes in black and white.
   • The Error Correction Mode (ECM) feature will only be available for color fax sending.
5. Try to send another fax.
   • If the fax is successful, then you were able to compensate for the telephone-line interference.
   • If the Comm. Error message continues to appear, follow these steps:
     1. Directly connect your Brother machine to a different, known-working telephone line and test the sending and receiving functions.
     2. Contact your telephone provider and have them test the line.
        • If the Comm. Error message continues to appear after you have the line checked and test the Brother machine on a different, known-working telephone line, please contact Brother Customer Service from "Contact Us."