Modem

- Enables you to connect your PC to a telephone.

- Modems have two RJ-11 sockets.
> One (1) connects the modem to the telephone jack on the wall,
> One (1) for an optional telephone


- External modems

> Traditionally connected to a male 9-pin or 25-pin D-subminiatureport on the system unit called a serial port (Figure 2-33)

>Although just about every external modem today connects to USB, most computers come with a serial port for legacy devices