What is the framing specification used for transmitting digital signals at 1.544 Mbps on a T1 facility?

A.
DS-0

B.
DS-1

C.
DS-2

D.
DS-3

Explanation:
Digital Signal Level 1 (DS – 1) provides 1.544 Mbps over a T1 line.
Incorrect Answers:
A: Digital Signal Level 0 (DS – 0) provides from 64 Kbps up to 1.544 Mbps on a Partial T1 line.
C: There is no framing specification named DS-2.
D: Digital Signal Level 3 (DS – 3) is a specification for T3, not for T1.

Stewart, James M., Ed Tittel, and Mike Chapple, CISSP: Certified Information Systems Security Professional
Study Guide, 5th Edition, Sybex, Indianapolis, 2011, p. 165