Integrated Services Digital Network (ISDN) is a set of communications standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network. the phone system was viewed as a way to transport voice, with some special services available for data.
When referring to a data connection, bandwidth, communication speed, or connection speed is the total maximum transfer rate of a network cable or device. modem connection. Essentially, it is a measurement of how fast data can be sent over a wired or wireless connection, usually measure in bits per second.