Also known as traditional telephone service or plain old telephone service (POTS), landline phone systems function over dedicated “phone-only” lines that connect to the user’s phone company. VoIP’s improved efficiency over internet lines allows for much lower rates than traditional service does, and shAlso known as traditional telephone service or plain old telephone service (POTS), landline phone systems function over dedicated “phone-only” lines that connect to the user’s phone company. VoIP’s improved efficiency over internet lines allows for much lower rates than traditional service does, and shared functionality with internet service eliminates the need for landline service entirely.ared functionality with internet service eliminates the need for landline service entirely.