See the following figure.
The configuration for Location 1, the dial-out side of the link, is composed of the following elements:
Dial-out machine, typically a personal computer or workstation in an individual's home.
Asynchronous modem or ISDN terminal adapter (TA) that is connected to a telephone jack.
Telephone lines and services of a telephone company.
The configuration for Location 2, the dial-in side of the link, is composed of the following elements:
Telephone jack or similar connector, which is connected to the telephone network
Asynchronous modem or ISDN TA
Dial-in server, which is connected to a network, such as a corporate intranet, or, in the instance of an ISP, the global Internet