In the 1960s, AT&T created a service known as ____, which multiplexed digital data and digitized voice onto a high-speed telephone line with a data rate of 1.544 megabits per second.

In the 1960s, AT&T created a service known as ____, which multiplexed digital data and digitized voice onto a high-speed telephone line with a data rate of 1.544 megabits per second.



a. ISDN c. SONET
b. T-1 d. SDH


Answer: B


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