BDS Customer Premises Equipment and Installation 2

Question 1

What does the upstream transmit power level of a cable modem indicate about the drop?

Accepted Answer

High transmit power (near or above 51 dBmV) indicates the modem is compensating for excessive signal loss in the drop or plant

Answer

A cable modem increases its transmit power during ranging to overcome high losses in the subscriber drop or distribution plant; levels consistently near the maximum (51–54 dBmV) indicate excessive attenuation that should be investigated.

Question 2

What is a cable set-top box (STB) and what are its main functions?

Accepted Answer

A customer premises device that tunes, decrypts, and decodes cable video channels for display on the television

Answer

A set-top box tunes to a specific downstream channel, decrypts the conditional access-protected content, decodes the MPEG video stream, and outputs audio/video to the connected television.

Question 3

What is a CableCARD and why was it introduced?

Accepted Answer

A removable conditional access module that allows retail TVs and devices to receive encrypted cable channels without a set-top box, mandated by the FCC to promote retail equipment

Answer

CableCARD is a PCMCIA-style card that contains the conditional access credentials, allowing consumers to use retail TVs and TiVo-style DVRs with cable service without renting an operator's set-top box.

Question 4

What is a whole-home DVR gateway and how does it differ from a single-room DVR?

Accepted Answer

A whole-home DVR gateway centrally records content and streams it to client devices throughout the home; a single-room DVR can only play recordings on the TV it is connected to

Answer

A whole-home DVR gateway centralizes recording and streaming, allowing multiple thin-client set-top boxes in any room to access recordings or live TV channels served from the gateway over the home's coax or Ethernet network.

Question 5

What causes a cable modem to repeatedly log T3 timeout errors?

Accepted Answer

The modem is not receiving a response to its upstream ranging requests, typically caused by upstream plant impairments, high noise, or incorrect upstream channel assignment

Answer

T3 timeouts occur when a cable modem sends a ranging request (RNG-REQ) but does not receive a ranging response (RNG-RSP) from the CMTS, usually due to upstream path impairments preventing the burst from reaching the headend.

BDS - Broadband Distribution Specialist Practice Test

BDS - Broadband Distribution Specialist Practice Test

BDS Customer Premises Equipment and Installation 2