Cisco modem

The Cisco DPQ3212 has a connection for coax cable and also what looks to be standard phone line. The phone line on my modem runs to an outlet market "MTA". 

What is the purpose of the phone line connection? In previous installations where I've had cable internet service, the modem did not have the second (phone line) connection. Is it needed for internet connectivity and functionality? 

Wanting to move everything to another room that has a coax cable jack, but no "MTA" outlet.