| Question 1 | Which channel is used by default for signaling for a T1 circuit? |
| A1: | Answer D is correct. Channel 23 is used by default for T1 signaling. Channel 15 is used on an E1, so Answer C is incorrect. 0 and 1 aren't used for signaling by default, so Answers A and B are incorrect. |
| Question 2 | You can examine the physical status of an interface with which command? A. show isdn event B. show isdn status C. debug q921 D. show interface bri
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| A2: | Answer B is correct. show isdn status gives the status of the physical interface. Answer A does not exist, Answer C shows communication between the router and the telco switch, and Answer D shows interface statistics so they are all incorrect. |
| Question 3 | What line-code options exist for configuration of a T1 circuit? A. AMI B. HDB3 C. B8ZS D. EMI
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| A3: | Answers A and C are correct. AMI is the older line code that is available, and B8ZS is the default. Answer B, HDB3, is the default for an E1, and Answer D, Electro Magnetic Interference (EMI), is something to avoid on a copper wire so both those answers are incorrect. |
| Question 4 | What command links an interface to a specific interesting traffic definition? A. dialer-map B. dialer-list C. dialer-interface D. dialer-group
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| A4: | Answer D is correct. The dialer-group command tells the interface which dialer list to use when deciding whether traffic is interesting. Answers A, B, and C are incorrect because a dialer interface is a logical interface, a dialer list specifies interesting traffic, and a dialer map links a phone number to a network address. |
| Question 5 | A BRI consists of A. 2D + B B. 2B + D C. 23B + D D. 31B + D
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| A5: | Answer B is correct. A BRI circuit has two B channels and a D channel. Answer A doesn't exist, Answer C is a T1, and Answer D is an E1. |
| Question 6 | What are valid values for a dynamically assigned TEI? |
| A6: | Answers B and C are correct. The range of dynamically assigned TEIs is 64 through 126. Answers A and D are incorrect because they fall outside the valid range. |
| Question 7 | Which T1 framing format supports a management channel? A. CRC4 B. No-CRC4 C. SF D. ESF
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| A7: | Answer D is correct. Extended Superframe (ESF) supports a 4Kbps management channel through occasional use of the 193rd bit in each frame. Answers A, B, and C, although frame types, do not support a management channel. |
| Question 8 | The U reference point has how many wires associated with it? |
| A8: | Answer A is correct. The U is a two-wire connection. Answers B, C, and D use more wires than are allowed. |
| Question 9 | The NT-1 is a device that converts _____ to _____. A. Two-wire, eight-wire B. Four-wire, eight-wire C. Two-wire, four-wire D. Four-wire, two-wire
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| A9: | Answer C is correct. The NT-1 converts the two-wire U to a four-wire S/T. Answers A, B, and D use numbers of wires that wouldn't work. |
| Question 10 | Which correctly describes bandwidth on the D channel? A. 32Kbps signaling + 32Kbps available B. 64Kbps signaling + 0Kbps available C. 48Kbps signaling + 16Kbps available D. 16Kbps signaling + 48Kbps available
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| A10: | Answer C is correct. The D channel uses 48Kbps for signaling and has 16Kbps that is available for other purposes. Answers A, B, and D have incorrect values for signaling bandwidth used and available bandwidth. |
