How Does Wireless Internet Work - A Simple Explanation

In this article I'll help you understand the answer to a computer terminology question I find a lot of people asking: "How does wireless Internet work?". Before I can answer this question, I have to mention that there are two basic types of wireless Internet: a wireless Internet connection through a device called a router (this type of wireless Internet is called WiFi), and then there is wireless Internet access through the cell phone network. 
Wireless routers are very common in homes, offices, and "wireless hotspots" like you find at coffee shops, airports, and elsewhere. These are basically just small electronic "boxes" that hook up to your Internet connection so you can share the connection between several computers, or simply to give you the freedom to place your computer wherever you want, and not just next to the cable or phone outlet.The cell phone data network (wireless Internet through the cell phone network in other words) of course is very widespread -- pretty much everywhere where you can get a cell signal -- and can be used not only with a cell phone but also with a growing number of computers.Now if you want to get really technical, these two types of wireless Internet work differently.  But in a general sense, if you simplify things and explain them in a basic way that will make sense to the average person, they both work along the same general lines.So how does wireless Internet work? One way to think of it is by comparing it to a portable phone. With a portable phone, something most of us have in our home, the phone has two parts: a handset and a cradle. The cradle gets plugged into the phone line -- the connection to the phone network -- and takes that connection and broadcasts it via radio waves more or less in all directions.If the handset is within range of the signal, it picks up this signal and relays the telephone connection so you can make or receive a call.Wireless Internet, whether its via a cell network or a wireless router, works the same basic way: you have a connection to the Internet, which is sent out wirelessly to a receiver of some sort, very much like a portable phone cradle sends out the telephone connection to the handset. The broadcast can come from a wireless router hooked up to a cable or DSL Internet connection, or the broadcast can be from a cell phone tower hooked into the cell phone network and relaying the Internet connection.On the other end you have a "handset", which is a receiver in a computer, smart phone, or other device. This could be a WiFi card in a laptop or desktop computer for the one type of wireless Internet, or a receiver in a cell phone or laptop using the cell data network.

Bluetooth interview questions


  1. Why is Bluetooth called a cable replacement technology? -Bluetooth technology allows the creation of Personal Area Networks without cables or wires that are usual in home networks.
  2. Give a generic description of Bluetooth? - Bluetooth is a low-cost, short-range (RF) links between mobile PCs, mobile phones and other portable devices. Bluetooth can transmit through solid, non-metal objects.
  3. Why can Bluetooth equipment integrate easily in TCP/IP network? - Because Bluetooth uses wireless LAN standards IEEE for data transmission.
  4. Is it possible to connect multiple Bluetooth hubs? - No, only one hub can be used at a time with a computer. USB or Serial devices can be added.
  5. What is FCC and how does it relate to Bluetooth? - FCC is Federal Communication Commission, which issues licenses to the stations for specific frequencies. It also decides who is able to use which frequency for what purpose. Since Bluetooth is using unlicensed spectrum, FCC has no direct involvement with Bluetooth
  6. Under what frequency range does Bluetooth work? - 2.45 GHz is the frequency range.
  7. Do Bluetooth devices need line of sight to connect to one another? - No.
  8. Which technology is used in Bluetooth for avoiding interference? - Frequency hopping is the technology used in Bluetooth.
  9. Bluetooth signals do not interfere with our PCs or cordless phones or portables. Why? - Bluetooth uses low-power signals, it plays around in 2.45 GHz range, while most of consumer devices would be using 900 MHz.
  10. What is Airport? - Airport is a wireless communications system, like Bluetooth. It is based on the IEEE 802.11 recommendation. It also uses 2.4 GHz frequency band, but its range is about 45 meters and it boasts a transmission speed of 11 Mbit/second. It is developed by Lucent Technologies.
  11. What is Piconet? - A collection of devices connected through Bluetooth technology in an ad hoc fashion.
  12. What are the three main types of connection used by Bluetooth? - Single slave, Master slave, Scatternet .
  13. What is FEC in Bluetooth? - Forward Error Correction is a method by which Bluetooth increases its noise immunity. FEC is a method that enables a receiver to not only detect, but also correct errors in a transmission.
  14. Which method is primarily used for Voice transfer? - Synchronous Connection Oriented (SCO) is a method primarily used for Voice transfer.
  15. What is the frequency range used for Bluetooth in Europe and United States? - 2402 MHz to 2480 MHz are the frequency ranges used in USA and Europe.
  16. List some Technology characteristic of Bluetooth? - Omni directional, Adaptive output power to minimize interference, Support Synchronous & asynchronous services, Fast Frequency Hopping to avoid interference, Short data packets to maximize capacity during interface.
  17. Which company originally conceived and developed Bluetooth? - Ericsson.
  18. How does Bluetooth use frequency hopping for security? - Bluetooth picks a random frequency out of 79 and then hops around the range about 1600 times per second.
  19. What is a Bluetooth dongle? - A device that hangs outside of a computer, or phone to provide Bluetooth connection.
  20. What are the other (competing or not) wireless technologies? - Wi-Fi, IrDa, EDGE, UWB (Ultra Wide Band)
  21. Which Bluetooth version uses adaptive frequency hopping? Why? - In Version 1.2 Adaptive frequency hopping method is used, which improves resistance to radio interference, and provides higher transmission speed.
  22. How many SCO links are there in a piconet? - In a piconet, there can be up to three SCO links of 64,000 bits per second each.
  23. what is the total number of masters and slaves in a piconet? - 1 Master and 7 Slaves.
  24. Which method is used for Data transfer? - Asynchronous Connectionless (ACL) is Data transfer method in Bluetooth
  25. What is the frequency range used for Bluetooth in Japan? - 2472 to 2497 MHz is the frequency range used for Bluetooth in Japan.
  26. What is the strength of the signal transmitted by powerful cell phones? - The powerful cell phones can transmit a signal of 3 watts.

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