BDS Customer Premises Equipment and Drop Systems 1 — Questions and Answers
Question 1: What is the maximum recommended length for a standard RG-6 coaxial drop cable from the tap to the customer's cable modem?
- 50 feet
- 100 feet
- 150 feet (Correct answer)
- 250 feet
Correct answer: 150 feet
The maximum recommended RG-6 drop cable length is typically 150 feet (approximately 45 meters) to ensure adequate signal levels reach the customer's equipment within DOCSIS specifications.
Question 2: What type of connector is used on RG-6 coaxial cable at customer premises equipment connections?
- N-type connector
- BNC connector
- F-type connector (Correct answer)
- SMA connector
Correct answer: F-type connector
The F-type connector is the standard coaxial connector used throughout US cable broadband drop plants and customer premises wiring for connecting cable modems, set-top boxes, and splitters.
Question 3: What is the purpose of a ground block on a customer's drop cable entry point?
- To reduce signal loss at the entrance to the home
- To provide a grounding point that protects equipment from lightning surges and satisfies NEC grounding requirements (Correct answer)
- To filter ingress from entering the home's internal wiring
- To boost the signal level before it enters the home splitter
Correct answer: To provide a grounding point that protects equipment from lightning surges and satisfies NEC grounding requirements
A ground block bonds the coaxial cable shield to the building's electrical ground system, providing a path for surge currents from lightning to safely dissipate rather than flowing through customer equipment.
Question 4: What is a eMTA (Embedded Multimedia Terminal Adapter)?
- A cable modem that includes a built-in VoIP ATA for telephone service (Correct answer)
- A set-top box with an integrated cable modem
- A fiber terminal that connects to the HFC node
- A DSL modem with VDSL2 support
Correct answer: A cable modem that includes a built-in VoIP ATA for telephone service
An eMTA combines a DOCSIS cable modem with an embedded Multimedia Terminal Adapter (MTA) for PacketCable VoIP telephone service, allowing subscribers to receive voice and data through a single device.
Question 5: What is the function of a signal splitter at customer premises?
- To amplify the signal for multiple television sets
- To divide the cable signal to feed multiple devices such as cable modems and televisions (Correct answer)
- To convert between coaxial and twisted-pair wiring
- To filter unwanted frequencies from the cable signal
Correct answer: To divide the cable signal to feed multiple devices such as cable modems and televisions
A customer premises splitter passively divides the incoming cable signal to feed multiple devices, with each split introducing approximately 3.5 dB of additional insertion loss.
Question 6: What is the recommended minimum downstream signal level at a cable modem input for reliable DOCSIS service?
- -20 dBmV
- -15 dBmV (Correct answer)
- 0 dBmV
- +10 dBmV
Correct answer: -15 dBmV
DOCSIS specifications define the minimum operational downstream level at -15 dBmV, below which modem performance degrades; optimal operation occurs between -7 dBmV and +7 dBmV.
BDS Customer Premises Equipment and Drop Systems 1
What is the maximum recommended length for a standard RG-6 coaxial drop cable from the tap to the customer's cable modem?