Question 1. What is the name of the gateway interface/port that faces an analog phone?

Foreign Exchange Office (FXO)

Foreign Exchange Subscriber (FXS)

Direct Inward Dialing (DID)

Dual-tone Multi-frequency (DTMF)

Question 2. Which of the following is a best practice, from the trunk service perspective, for improving the availability of an enterprise voice system?

Redundant local loops.

Separate entry points for trunks (or access lines) to enter a building.

Access trunks from two carriers.

All of the above

Question 3. The _____ information is sent into the trunk when placing an E911 call.

Calling Line ID (CLID)

Time Division Multiplexing (TDM)

Dual-tone Multi-frequency (DTMF)

Network Address Translation (NAT)

Question 4. Hundred seconds of total holding time during the Busy Hour generates a traffic load of _____.

1 Erlang

1 CCS

36 Erlang

60 CCS

Question 5. Calculate the number of CCS that is equivalent to 2 Erlangs.

2

72

120

200

Question 6. Given that the traffic load remains the same, which of the following call blocking probabilities will demand more trunk resources (e. g., trunk circuits)?

1%

2%

3%

4%

Question 7. A device that translates signaling formats between SIP and H.323, SIGTRAN, ISDN, channel associated signaling (CAS), or SS7.

Media Gateway

Softswitch

Session Initiation Protocol (SIP) Proxy

Session Border Controller (SBC)

Question 8. Give the following data during the busy hour: 200 out of 210 call attempts were completed, calculate the call blocking probability.

5.0%

4.8 %

95.2%

9.52%

Question 9. Calculate the number of Erlangs that is equivalent to 100 CCS.

3.5

2.8

5.6

9.2

Question 10. Calculate the utilization of a T1 trunk that on average carries 0.926 Mbps of traffic.

16.7%

62%

1.67%

0.6%