PPSC - Past Papers - Most Repeated — Test 4

Correct Answer: A. A. Wavelength division multiplexing (wdm)
Explanation: Wavelength Division Multiplexing (WDM) is a multiplexing technique that combines a number of optical signals into a single optical fiber. It combines wavelength of these different optical carrier signals and helps in increasing the capacity of optical fibers by decreasing the transmission loss.

Correct Answer: A. A. Ieee 802.3 mac header and network layer ip header
Explanation: MPLS (Multiprotocol Label Switching) label is highly scalable. It operates at the interface between network layer and link layer of the OSI model. Therefore, in an IP based protocol, MPLS label is positioned between IEEE 802.3 MAC header and Network layer IP header.

Correct Answer: A. A. Personal area network
Explanation: Bluetooth is an example of Wireless technology that is used for exchanging data over short distances. It also provides secure wireless communication. Thus, such a secure and short ranged technology is used Personal Area Networks.

Correct Answer: D. D. It is a group of interconnected piconets
Explanation: Scatternet is a network connecting two or more Piconets having Bluetooth technology incorporated in their network devices. It supports communication between more than 8 devices. Thus, Scatternet can also be defined as interconnected Piconets.

Correct Answer: A. A. True
Explanation: Personal Communication Services (PCS) and Digital Cellular Services are the two advanced segments of wireless technology. These segments are important for data communication. Thus they are based on cellular technology and rely on multiple access principle.

Correct Answer: C. C. Directional antenna
Explanation: Directional Antenna helps in increasing the gain of a signal in forward direction or one particular direction. It is also known as beam antenna. It avoids interference of unwanted signals.

Correct Answer: A. A. By hiding nodes in a network
Explanation: In wireless communications, there exists a hidden node problem. This occurs when a node or a station is to an Access Point but not to other stations communicating with the Access Point. The main reason behind this is that the stations are out of range of each other and thus collisions cannot be detected.

Correct Answer: D. D. 2.402 ghz, 2.480 ghz
Explanation: The frequency band for Bluetooth communication is set by an international agreement. This frequency band is between 2.402 GHz and 2.480 GHz.

Correct Answer: B. B. Integrated services digital network
Explanation: ISDN in computer networking stands for Integrated Services Digital Network. It enables the transmission of digital data over telephone lines. It is considered as a circuit-switched telephone network system.

Correct Answer: C. C. Narrow band, broadband
Explanation: Narrowband ISDN was implemented to make digital telephone systems more impactful over analog telephone systems. It utilizes narrow band of frequencies. Narrowband is also known as Normal-ISDN. Broadband ISDN on the other hand, is a standard for transmitting voice data on larger frequency bands.