Lexmark XC4150
A distinctive ring service lets you have multiple telephone numbers on one telephone line. Each telephone number is assigned a different ring pattern.
From the home screen, touch Settings > Fax > Analog Fax Setup > Fax Receive Settings > Admin Controls > Answer On.
Select the ring pattern.
Apply the changes.
Connect your printer directly to an active telephone wall jack or share a line with an answering machine or voice mail service.
Here are troubleshooting steps when unable to 'Send' a fax with Laser Multifunction Printers (MFPs).