Below are some important Bluetooth interview questions which are asked in most MNC company interviews for beginners or professionals.
1. Why is Bluetooth 2.0 better?
The main features of Bluetooth Core Specification Version 2.0 + EDR are:
• 3 times faster transmission speed (up to 10 times in certain cases)
• Lower power consumption through reduced duty cycle
• Simplification of multi-link scenarios due to more available bandwidth
• Backwards compatible to earlier versions
• Further improved BER (Bit Error Rate) performance
2. Name few applications of Bluetooth?
* Wireless control of and communication between a cell phone and a hands free headset or car kit. This is the most popular use.
* Wireless networking between PCs in a confined space and where little bandwidth is required.
* Wireless communications with PC input devices such as mouses and keyboards and output devices such as printers.
* Transfer of files between devices via OBEX.
* Transfer of contact details, calendar appointments, and reminders between devices via OBEX.
* Replacement of traditional wired serial communications in test equipment, GPS receivers and medical equipment.
* For remote controls where infrared was traditionally used.
* Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices.
* Wireless control of a games console, Nintendo’s Wii and Sony’s PlayStation 3 will both use Bluetooth technology for their wireless controllers.
* Sending commands and software to the upcoming LEGO Mindstorms NXT instead of infra red.
3. How many devices can communicate concurrently?
A Bluetooth device playing the role of the “master” can communicate with up to 7 devices playing the role of the “slave”. This network of “group of up to 8 devices” (1 master + 7 slaves) is called a piconet. A piconet is an ad-hoc computer network of devices using Bluetooth technology protocols to allow one master device to interconnect with up to seven active slave devices (because a three-bit MAC address is used). Up to 255 further slave devices can be inactive, or parked, which the master device can bring into active status at any time.
4. What is Pairing?
Pairs of devices may establish a trusted relationship by learning (by user input) a shared secret known as a “passkey”. A device that wants to communicate only with a trusted device can cryptographically authenticate the identity of the other device. Trusted devices may also encrypt the data that they exchange over the air so that no one can listen in. The encryption can however be turned off and passkeys are stored on the device’s file system and not the Bluetooth chip itself. Since the Bluetooth address is permanent a pairing will be preserved even if the Bluetooth name is changed. Pairs can be deleted at any time by either device. Devices will generally require pairing or will prompt the owner before it allows a remote device to use any or most of its services. Some devices such as Sony Ericsson phones will usually accept OBEX business cards and notes without any pairing or prompts. Certain printers and access points will allow any device to use its services by default much like unsecured Wi-Fi networks.
5. How secure a Bluetooth device is?
Bluetooth uses the SAFER+ algorithm for authentication and key generation. The E0 stream cipher is used for encrypting packets. This makes eavesdropping on Bluetooth-enabled devices more difficult.
6. What is Bluetooth SIG?
Bluetooth Special Interest Group (SIG)
Bluetooth wireless technology is revolutionizing personal connectivity by providing freedom from wired connections. It is a specification for a small-form factor, low-cost radio solution providing links between mobile computers, mobile phones, other portable handheld devices and automobiles, as well as connectivity to the Internet. The Bluetooth SIG, comprised of leaders in the telecommunications, computing, automotive and consumer electronics industries, is driving development of the technology and bringing it to market. The Bluetooth SIG includes Promoter member companies Agere, Ericsson, IBM, Intel, Microsoft, Motorola, Nokia and Toshiba, and thousands of Associate and Adopter member companies. The Bluetooth SIG, Inc. headquarters are located in Overland Park, Kansas, U.S.A.
7. What are the problems with older versions (1.0 and 1.0 B)?
Versions 1.0 and 1.0 B had numerous problems and the various manufacturers had great difficulties in making their products interoperable. 1.0 and 1.0B also had mandatory Bluetooth Hardware Device Address (BD_ADDR) transmission in the handshaking process, rendering anonymity impossible at a protocol level, which was a major setback for services planned to be used in Bluetooth environments, such as Consumerism.
8. What are Different Classes in Bluetooth?
Bluetooth is a radio standard and communications protocol primarily designed for low power consumption, with a short range (power class dependent: 1 meter, 10 meters, 100 meters) based around low-cost transceiver microchip in each device.
Bluetooth lets these devices communicate with each other when they are in range. The devices use a radio communications system, so they do not have to be in line of sight of each other, and can even be in other rooms, so long as the received power is high enough.
9. What are Bluetooth profiles?
A profile is a description of how to use a specification to implement a particular function. The International Standards Organization (ISO) first came up with the idea of profiles. In Bluetooth, there are several profiles available and they are arranged in a hierarchical fashion. For example, in order to use the headset profile, a device must also include the lower level profiles such as the serial port and general access profiles.
10. What are some of the uses of Bluetooth?
Depending on the Bluetooth profiles included on the device, Bluetooth technology has the capability to wirelessly synchronize and transfer data among devices. The Bluetooth audio capabilities can be used for headset and hands free applications. The exact functionality provided by a Bluetooth enabled device depends on the Bluetooth profiles included.
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1. Why is Bluetooth 2.0 better?
The main features of Bluetooth Core Specification Version 2.0 + EDR are:
• 3 times faster transmission speed (up to 10 times in certain cases)
• Lower power consumption through reduced duty cycle
• Simplification of multi-link scenarios due to more available bandwidth
• Backwards compatible to earlier versions
• Further improved BER (Bit Error Rate) performance
2. Name few applications of Bluetooth?
* Wireless control of and communication between a cell phone and a hands free headset or car kit. This is the most popular use.
* Wireless networking between PCs in a confined space and where little bandwidth is required.
* Wireless communications with PC input devices such as mouses and keyboards and output devices such as printers.
* Transfer of files between devices via OBEX.
* Transfer of contact details, calendar appointments, and reminders between devices via OBEX.
* Replacement of traditional wired serial communications in test equipment, GPS receivers and medical equipment.
* For remote controls where infrared was traditionally used.
* Sending small advertisements from Bluetooth enabled advertising hoardings to other, discoverable, Bluetooth devices.
* Wireless control of a games console, Nintendo’s Wii and Sony’s PlayStation 3 will both use Bluetooth technology for their wireless controllers.
* Sending commands and software to the upcoming LEGO Mindstorms NXT instead of infra red.
3. How many devices can communicate concurrently?
A Bluetooth device playing the role of the “master” can communicate with up to 7 devices playing the role of the “slave”. This network of “group of up to 8 devices” (1 master + 7 slaves) is called a piconet. A piconet is an ad-hoc computer network of devices using Bluetooth technology protocols to allow one master device to interconnect with up to seven active slave devices (because a three-bit MAC address is used). Up to 255 further slave devices can be inactive, or parked, which the master device can bring into active status at any time.
4. What is Pairing?
Pairs of devices may establish a trusted relationship by learning (by user input) a shared secret known as a “passkey”. A device that wants to communicate only with a trusted device can cryptographically authenticate the identity of the other device. Trusted devices may also encrypt the data that they exchange over the air so that no one can listen in. The encryption can however be turned off and passkeys are stored on the device’s file system and not the Bluetooth chip itself. Since the Bluetooth address is permanent a pairing will be preserved even if the Bluetooth name is changed. Pairs can be deleted at any time by either device. Devices will generally require pairing or will prompt the owner before it allows a remote device to use any or most of its services. Some devices such as Sony Ericsson phones will usually accept OBEX business cards and notes without any pairing or prompts. Certain printers and access points will allow any device to use its services by default much like unsecured Wi-Fi networks.
5. How secure a Bluetooth device is?
Bluetooth uses the SAFER+ algorithm for authentication and key generation. The E0 stream cipher is used for encrypting packets. This makes eavesdropping on Bluetooth-enabled devices more difficult.
6. What is Bluetooth SIG?
Bluetooth Special Interest Group (SIG)
Bluetooth wireless technology is revolutionizing personal connectivity by providing freedom from wired connections. It is a specification for a small-form factor, low-cost radio solution providing links between mobile computers, mobile phones, other portable handheld devices and automobiles, as well as connectivity to the Internet. The Bluetooth SIG, comprised of leaders in the telecommunications, computing, automotive and consumer electronics industries, is driving development of the technology and bringing it to market. The Bluetooth SIG includes Promoter member companies Agere, Ericsson, IBM, Intel, Microsoft, Motorola, Nokia and Toshiba, and thousands of Associate and Adopter member companies. The Bluetooth SIG, Inc. headquarters are located in Overland Park, Kansas, U.S.A.
7. What are the problems with older versions (1.0 and 1.0 B)?
Versions 1.0 and 1.0 B had numerous problems and the various manufacturers had great difficulties in making their products interoperable. 1.0 and 1.0B also had mandatory Bluetooth Hardware Device Address (BD_ADDR) transmission in the handshaking process, rendering anonymity impossible at a protocol level, which was a major setback for services planned to be used in Bluetooth environments, such as Consumerism.
8. What are Different Classes in Bluetooth?
Bluetooth is a radio standard and communications protocol primarily designed for low power consumption, with a short range (power class dependent: 1 meter, 10 meters, 100 meters) based around low-cost transceiver microchip in each device.
Bluetooth lets these devices communicate with each other when they are in range. The devices use a radio communications system, so they do not have to be in line of sight of each other, and can even be in other rooms, so long as the received power is high enough.
9. What are Bluetooth profiles?
A profile is a description of how to use a specification to implement a particular function. The International Standards Organization (ISO) first came up with the idea of profiles. In Bluetooth, there are several profiles available and they are arranged in a hierarchical fashion. For example, in order to use the headset profile, a device must also include the lower level profiles such as the serial port and general access profiles.
10. What are some of the uses of Bluetooth?
Depending on the Bluetooth profiles included on the device, Bluetooth technology has the capability to wirelessly synchronize and transfer data among devices. The Bluetooth audio capabilities can be used for headset and hands free applications. The exact functionality provided by a Bluetooth enabled device depends on the Bluetooth profiles included.
More Questions & Answers :-
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