NCTI: Troubleshooting Advanced Services
Which of the following channels represents a well performing network?
A channel that is utilized less than 50% of the time
Which of the following digital TV (DTV) trouble calls could have been avoided with customer education about the product?
STB Overheating; IR Sensor; VOD recording; Occasional freezing
Which 802.11 standard takes more time to send and receive data, thus causing congestion on the 2.4 GHz band?
802.11b
What type of digital television (DTV) artifact describes moving lines and changing colors across patterns with repeated symmetrical detail?
The moiré effect.
What non-Wi-Fi device utilizes 20 MHz of spectrum, which is nearly the same as a Wi-Fi network and, due to its heavy utilization, can cause a Wi-Fi network to stop working entirely?
Analog wireless security camera
Which of the following is a form of isolating elements during troubleshooting?
Eliminating possible causes.
If a High-Definition Multimedia Interface (HDMI) splitter is suspected as the cause of a problem, how can the splitter be tested?
Bypass the splitter by connecting only one device at a time using the same HDMI cable.
When replacing a splitter to resolve a digital TV (DTV) service problem, what does confirming the splitter output levels before attaching the output connectors do?
Confirmation reinforces the technician's confidence that the problem will be resolved by replacing the splitter.
During which step of the six-step troubleshooting process for a digital TV (DTV) service problem are quadrature amplitude modulation (QAM) channel measurements typically taken?
Diagnose
When analyzing loss of lip sync at the customer premises, what does seeing the same issue on multiple channels tell you?
The problem is coming from the set-top box (STB), TV, or other equipment in the customer premises.
When diagnosing an Internet protocol television (IPTV) service problem in the customer premises, what can be concluded if the problem goes away when the streaming media player is connected to the local area network (LAN) with an Ethernet cable rather than Wi-Fi?
The problem is isolated to the Wi-Fi network.
Why is switching the Wi-Fi frequency of a streaming media player to the 5 gigahertz (GHz) band a possible solution to avoid interference from neighboring networks?
The signal propagation at 5 GHz is lower and interference from neighboring networks is less likely than at 2.4 GHz.
What must a technician be aware of when analyzing a digital TV (DTV) problem?
There is frequently more than one contributor to a specific DTV service problem.
What should you do if a client device keeps defaulting to the 2.4 GHz network over the 5 GHz network?
Use different service set identifiers (SSID) for each network
What is the minimum Wi-Fi signal strength for reliable, timely delivery of streamed Internet protocol television (IPTV) content?
-67 to -65 decibels milliwatt (dBm).
What is the maximum signaling rate for a 3SS device (premium laptop)?
195 megabits per second (Mbps)
What should a technician do if Wi-Fi signal strength appears to be too low for what the customer is trying to use the network for?
Set expectations with the customer by explaining the signal strength issue
Which of the following characterizes the successful troubleshooter?
Someone with an inquisitive and relentless desire to solve and fix problems.
Although the cables seldom cause a High-Definition Multimedia Interface (HDMI) interoperability issue, why is it still a good practice to swap cables?
It is usually easy and eliminates the HDMI cable as a potential cause of an interoperability problem.
After a digital TV (DTV) service problem has been analyzed and possible causes considered, what is accomplished by isolating the various network elements?
It narrows the scope of likely problem sources.
Because the spectral density of a quadrature amplitude modulation (QAM) channel is much higher than that of an analog TV channel, what is done to ensure equal power in all channels in a network with analog and digital modulation channels?
Operate the analog TV channels at higher amplitude level than the QAM channels.
What other device factors determine what speeds a device will achieve over a Wi-Fi network?
Processor storage read/write space and
What could be done if Co-channel interference is found to be the reason for slower data rates?
Switch the network to another channel that is less congested
A narrow slice of spectrum appears on the 2.4 GHz band that may or may not cause congestion when this button is pressed on a 2.4 GHz cordless phone?
Talk
What does a set-top box (STB) diagnostic page of a quadrature amplitude modulation (QAM) channel showing signal-to-noise ratio (SNR) near or below 30 dB indicate?
The QAM channel quality is on the edge for reliable reception, and the source of the problem is likely in the distribution network or customer premises.
What does a good modulation error ratio (MER) measurement of a quadrature amplitude modulation (QAM) channel with digital television (DTV) artifacts indicate?
The artifacts are created before modulation.
What does the two-way capabilities of the High-Definition Multimedia Interface (HDMI) enable to protect full-resolution high definition television (HDTV) content from being copied and sold illegally?
High-bandwidth digital content protection (HDCP).
What could you do if there are no good channel options in the 2.4 GHz band for your customer's 802.11n device?
If available, connect devices with Ethernet
When troubleshooting a digital TV (DTV) authorization issue, what can be verified using the set-top box (STB) diagnostic page?
STB reception of authorization message data
Which type of set-top box (STB) operates more like Data Over Cable Service Interface Specification (DOCSIS) cable modems with return channels on the same frequencies used for cable modems?
STB with DOCSIS Set-top Gateway (DSG) client software and embedded DOCSIS modems.
