RJ-11
Definition:
RJ-11 is the type of connection used by standard phone lines. Home telephones, fax machines, and computer modems all connect through RJ-11 jacks.
Here's a word you may not know...
operating system
In the simplest terms, an operating system (OS) gives people a way to communicate with computer hardware such as the motherboard, video driver, power supply, CD/DVD Drive and hard disk storage. The OS manages and coordinates activities, provides security, allocates resources and hosts applications so your computer "just works." In fact, it's what you see when you boot your computer and before you launch software.