The D channel in ISDN is an example of which two signaling methods? (Choose two.)
A.
CCS signaling
B.
out-of-band signaling
C.
in-band signaling
D.
CAS signaling
Explanation:
There are two types of ISDN lines: Basic Rate ISDN (BRI) and Primary Rate ISDN (PRI). Both BRI and PRI types have the same 64kbps D channel that is used for call supervision. This D channel is dedicated for signaling only and contains all the necessary signaling for establishing call between two end-points so it is a kind of CCS signaling and out-of-band signaling.