Q7. Which of the following are reference points relevant to ISDN? [Select 2].
A. T
B. U
C. V
D. S
Correct Answer: A,B,D
Explanation:
ISDN uses four different reference points to define logical interfaces:
1. R-reference point: Defines the reference point between non-ISDN compatible devices and a Terminal Adapter (TA).
2. S-reference point: Defines the reference point between user terminals and an NT2.
3. T-reference point: Defines the reference point between NT1 and NT2.
4. U-reference point: Defines the reference point between NT1 devices and line-termination equipment in a carrier network.
The flow of reference points are:
[TE2] ---R--->[TA]---S/T--->[NT1]--->U--->to carrier
[TE2]--->R--->[TA]--->S--->[NT2]--->T--->[NT2]--->to carrier
Disclaimer: Simulationexams.com is not affiliated with any certification vendor, and Sim-Ex™ Practice Exams are written independently by SimulationExams.com and not affiliated or authorized by respective certification providers. Sim-Ex™ is a trade mark of SimulationExams.com or entity representing Simulationexams.com.CCNA™ is a trademark of Cisco® systems
