Jennifer Paoletti

Chris Pannozzo

Christopher Stern
October 25,2007

CSC 101-02

Midterm Exam

 

Ethernet - Ethernet is a local-area network (LAN) technology, used in both wired and wireless LAN connections.  Ethernet was first developed by Xerox from "Alohanet", and then developed by Xerox, DEC, and Intel.  It was named "ethernet" by Robert Metcalfe to describe how cabling carries data throughout a network.  Ethernet is usually used to power a LAN network, to connect multiple computers together with high-speed data transfer. 

http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci212080,00.html

 

ZigBee - ZigBee is a method of wireless communication developed by the ZigBee Alliance, using low-power digital radio.  It is intended to be cheaper and simpler than other methods of wireless connectivity.  Its primary usage is for low-data, low-power transfer, such as powering home devices like smoke and intruder alarms, and making such devices last even longer. 

http://en.wikipedia.org/wiki/ZigBee

 

FireWire 400

FireWire 400 can transfer data between devices at 100, 200, or 400 mbit/s data rates (the actual transfer rates are 98.304, 196.608, and 393.216 mbit/s i.e. 12.288, 24.576 and 49.152 MBytes per second respectively). These different transfer modes are commonly referred to as S100, S200, and S400.

Cable length is limited to 4.5 metres (14.8 ft), although up to 16 cables can be daisy chained using active repeaters, external hubs, or internal hubs often present in FireWire equipment. The S400 standard limits any configuration's maximum cable length to 72 meters. The 6-pin connector is commonly found on desktop computers, and can supply the connected device with power. A 4-pin version is used on many laptops (although some use the 6-pin powered connector, particularly those made by Apple) and small FireWire devices and does not have any power connectors, although it is fully compatible with 6-pin interfaces.

The 6-pin powered connector adds power output to support external devices. Typically a device can pull about 7 to 8 watts from the port; however, the voltage varies significantly from different devices. Voltage is specified as unregulated and should nominally be about 25 Volts (range 24 to 30). Apple's implementation on laptops is typically related to battery power and can be as low as 9V and more likely about 12V.

Although high-speed USB 2.0 runs at a higher signalling rate (480 Mbit/s), typical PC-hosts rarely exceed sustained transfers of 35 MB/s, with 30 MB/s being more typical (the theoretical limit for a USB 2 high-speed bulk transfer is 53.125 MB/s). This is likely due to USB's reliance on the host-processor to manage low-level USB protocol, whereas Firewire automates the same tasks in the interface hardware. For example, the firewire host interface supports memory-mapped devices, which allows high-level protocols to run without loading the host CPU with interrupts and buffer-copy operations.

FireWire 800

FireWire 800 (Apple's name for the 9-pin "S800 bilingual" version of the IEEE 1394b standard) was introduced commercially by Apple in 2003. This newer 1394 specification (1394b) and corresponding products allow a transfer rate of 786.432 Mbit/s with backwards compatibility to the slower rates and 6-pin connectors of FireWire 400. However, while the IEEE 1394a and IEEE 1394b standards are compatible, FireWire 800's connector is different from FireWire 400's connector, making the physical male and female (both 4 and 6pin) connectors and cables incompatible. An adapter is necessary to take advantage of the 800's backward compatibility.

The full IEEE 1394b specification supports optical connections up to 100 meters in length and data rates up to 3.2 gbit/s Standard category-5 unshielded twisted pair supports 100 metres at S100, and the new p1394c technology goes all the way to S800. The original 1394 and 1394a standards used data/strobe encoding on the signal wires, while 1394b adds a data encoding scheme called 8b10b With this new technology, FireWire, which was already slightly faster is now substantially faster than Hi-Speed USB.

Created by: Apple

http://www.eetimes.com/news/latest/showArticle.jhtml?articleID=187002039

http://en.wikipedia.org/wiki/Firewire

Bluetooth:

 A wireless personal area network (WPAN) technology from the Bluetooth Special Interest Group (www.bluetooth.com) founded in 1998 by Ericsson, IBM, Intel, Nokia and Toshiba. Bluetooth is an open standard for short-range transmission of digital voice and data that supports point-to-point and multipoint applications. Some of the first Bluetooth applications have been for cellphones, providing a wireless connection to a headset and to an automobile's audio system for hands-free operation.

Bluetooth is in a variety of new products such as phones, printers, modems, and headsets. Bluetooth is acceptable for situations when two or more devices are in close proximity with each other and don't require high bandwidth. Bluetooth is most commonly used with phones and handheld computing devices, either using a Bluetooth headset or transferring files from phones/PDAs to computers. Since Bluetooth uses short-range radio frequencies, it is not as effective for setting up networks that can be accessed from remote locations as Wi-Fi is.

Bluetooth also simplified the discovery and setup of services. Wi-Fi is more analogous to the traditional Ethernet network and requires configuration to set up shared resources, transmit files, set up audio links (e.g. headsets and hands-free devices), whereas Bluetooth devices advertise all services they actually provide; this makes the utility of the service that much more accessible, without the need to worry about network addresses, permissions and all the other considerations that go with typical networks.

Bluetooth 1.1 :

• Many errors found in the 1.0B specifications were fixed.

• Added support for non-encrypted channels.
• Received Signal Strength Indicator (RSSI)
• http://computing-dictionary.thefreedictionary.com/Bluetooth+1.1

Bluetooth 2.0 :

 This version is backwards compatible with 1.x. The main enhancement is the introduction of Enhanced Data Rate (EDR) of 3.0 Mbps. This has the following effects (Bluetooth SIG, 2004):

• 3 times faster transmission speed (up to 10 times in certain cases).
• 100 meter range
• Lower power consumption through a reduced duty cycle.
• Simplification of multi-link scenarios due to more available bandwidth.
• Further improved BER (bit error rate) performance.

http://www.thefreedictionary.com/_/google.aspx?q=Bluetooth+2.0