a. Why is the PSTN important in WAN data transmission?

5a.) How do WAN carriers typically get their trunk lines?

a. They construct them.

b. They lease them from telephone companies.

c. They use wireless transmission.

d. They use the Internet.

b. What is the local loop?

5b.) In the telephone system, the lines that connect customers to the nearest switch are called ________.

a. Trunk lines

b. Local lines

c. The access loop

d. The local loop

c. What class of switches are most end office switches?

5c.) Most end-office switches are Class ________ switches.

a. 1

b. 2

c. 4

d. 5

d. What is the structure of the PSTN core?

5d.) The PSTN core is organized as a ________.

a. Mesh

b. Hierarchy

c. Modified hierarchy

d. Loop