This is a Sportster® 33.6 kbps modem by US Robotics. 
It sends and receives faxes through the computer while running other applications, sends group and delayed faxes, and creates personalized phone books for quicker dialing.
It can permanently store preferred modem default settings, and it has built-in processing power that handles the processing for the connection, so the computer doesn’t have to do the work.

The fax modem's lifespan basically concluded around 2003 when emailing began easier to use and Internet speeds became faster, allowing for email to be a more viable form of communication. As such, with email improving, the need for faxing messages or documents was decreasing. Fax machines are bulky and big and loud whereas email is on the Internet and silent. It takes up no physical room. Fax machines are still used sparsely today but they are certaintly not essential pieces of technology anymore.