various lines for communication over telephone network
Different lines for communication over telephone network are as follows:
ISDN stands for Integrated Services/digital Network. It is a set of standards for digital transmission of data over standard copper telephone lines. One telephone line can carry three or more signals at one time using the same line. ISDN requires ISDN modem at both sides. ISDN modem is different from dial-up modem.
DSL stands for digital subscriber line. It provides high-speed data transmission over existing telephone lines. The existing telephone lines are analog. That is why, DSL modem is required to connect to DSL. DSL is easier to install than ISDN and is also faster.