The Brother MFC 7840W comes with three different equalization settings to accommodate different types of connections for the device’s fax line. The ECM or error correction mode will create too much interference if you connect the device to a voice over IP or VoIP line, such as phone service you get through your cable company that runs through a modem. Turning off the ECM mode on the device only takes a few moments to complete.
Press the MFC 7840W’s “Power” button to turn the device on. Wait for the device to fall silent, signaling it has finished its warm up procedures before continuing.
Press the “Menu” button on the device’s control panel. Press the “2” then “0” then “1” keys on the numeric keypad on the device’s control panel.
Use the up and down arrow keys to cycle through the device’s Equalization settings. Once the display screen reads “Basic” stop pressing the arrow keys.
Press the “OK” button on the control panel to save your setting. Press the “Stop/Exit” button to leave the menu and continue using the device.