MIS Critical Thinking
What is the difference between fiber optic cable and twisted pair cable? Fiber optic cabling transmits light rather than electricity. It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting. Fiber optic cable has the ability to transmit signals over much longer distances than twisted pair cable. It also has the capability to carry information at vastly greater speeds.
What are the data communications equipment (DCE) devices? Modems (asynchronous and synchronous), Channel service unit/data service unit (CSU/DSU), Multiplexers. A DCE device typically has a female connector.
What is a Multiplexer? Multiplexer is a device that merges information from multiple input channels to a single output channel. What does it do? A multiplexer electronic device that time multiplexes video pictures from numerous cameras onto one VCR. This means that one field or frame from one camera was switched to the VCR, then immediately following that picture was another field or frame from another camera and so on from each camera, and then it started over again.
Why is twisted pair cable so popular? Twisted-pair cables are very popular. Telephone systems use twisted-pair cable which is already installed in most buildings. Therefore, its availability is making it a popular choice for computer networking if the particular cable is of sufficient grade to support data transmission. Twisted pair cable is inexpensive, flexible, easy to manage, and very reliable. As stated in Networking Essentials, Second Edition, by Microsoft Press, “Twisted-pair cabling consists of two insulated strands of copper wire twisted around each other. A number of twisted-pair wires are often grouped together and enclosed in a protective sheath to form a cable. The actual number of pairs in a cable varies. The twisting cancels out electrical noise from adjacent pairs and from other sources such as motors, relays, and transformers”(86). Twisted-pair cable supports a transmission speed of 10 Mbps and uses RJ-45 connectors to attach the cable to the computer.
What is the difference between single mode and multimode fiber? Single mode fiber An optical fiber that supports only one mode of light propagation above the cutoff wavelength.
Multimode fiber supports more than one propagating mode of light.
What is the bandwidth capacity of single mode fiber? Single mode fiber put through a signal at 10Mbps
What is the modem standard? A European standard organization called the Comité Consultatif International Téléphonique et Télégraphique (CCITT) establish standards for modems. These standards, called the V standards define the speed at which modems can modulate.
What are the most popular modem standards?
• V.22 Shares the features of V.21, but was capable of 1200bps. Later, the V.22bis protocol was used. It was used both in the U.S. and outside, and ran at 4 bits per baud for a total of 2400bps.
• V.23 Used mainly in Europe, this allowed the modem to send and receive data at the same time, although it could send data only at 75bps. This standard was developed to lower the cost of modems. A 1200 bps modem was very expensive at the time.
• V.29 A half-duplex standard, meaning one-way. It works at 9600bps. The standard is not laid out well for modems, therefore isn’t much used. The protocol is most often used for fax machines.
• V.32 this standard began to get users into the ballpark we are all in now. It was a full-duplex standard and operated at 9600bps, with a 2400 baud rate. It incorporates error-correcting and negotiation. The error-correcting allowed V.32 to work well over phone line noise.
• V.32bis this is one step up from V.32. It transmitted 6 bits per baud, allowing throughputs of 14,400 bps. It also allowed fallback onto regular V.32 if the phone line was impaired. Many still use this modem standard primarily.
• V.32 fast Better known as the 28,800 bps modem.
• V.34 the latest real modem standard. It provides a reliable 28,800 bps connection. With upgrades to the ROM BIOS on the modem, the standard is often used for 33,600 bps transmissions.
• V.92 up stream rates increase up 48Kbps. Also has quick connection feature which implements faster handshaking to cut connection delays.
Citation
Hallberg, Bruce. Networking A beginner’s Guide. 3rd ed. Berkeley: McGraw Hill/Osbourne, 2003.
(Hallberg 490)
Dodd, Annabel. The Essential Guide to Telecommunication. 3rd ed. Upper Saddle River: Prentice Hall PTR, Upper Saddle River, NJ 07458 http://www.phptr.com, 2002.
(Dodd 500)
Habraken, Joe. Absolute Beginner’s Guide to Networking. 3rd ed. Indianapolis: Que, 2001.
(Habraken 442)