PDAs vs. PCs: Networks



		Networks The physical nature of handheld and desktop computers influences how they connect to and use networks. The most common way of accessing a network today is with a personal desktop computer through physical lines by way of a modem or Ethernet adapter. Handhelds, on the other hand, are constantly mobile need a way of connecting to networks wirelessly. Plugging a handheld computer into a physical network is contradictory to the nature of the device. This wireless industry is still in its infancy, but new technologies are showing some promise. Serial Cable: The most basic form of networking a handheld is by connecting it to a computer through a serial cable. This is used to exchange, or sync, data (programs, notes, addresses, etc..) between the handheld device and a PC. This is good for backing up information stored on the handheld. This form of networking is primitive and is not sufficient fortoday's needs. IrDA: IrDA is a standard governed by The Infrared Data Association that allows for wireless "data connection using infrared light". As described on the IrDA's website "it is a low-cost transceiver signaling technology for two way data exchange. It provides high-speed digital exchange through the typical PC UART/serial port at 9600-115200 bits/s, and in some units compatible high speed extensions up to 1Mb/s and 4Mb/s speeds". The distance limitation of a meter as well as the need to have an open path between ports limits this technology, but it still has its benefits. IrDA is the most ubiquitous way of transferring information from one handheld to another since most devices come equipped with a port. People use it to send virtual business cards, notes, or play games. For more information check out: http://www.irda.org/index.asp http://www.irda.org/products/IR%20Enabled%20Products%20List.pdf Bluetooth: Bluetooth is another inexpensive solution to short-range, wireless networking. Unlike IrDA, which operate on infrared, Bluetooth runs over the global radio frequency of 2.4 GHz. Bluetooth devices can achieve up to 1 Mb/s transfer rates at a range of up to 10 meters. This technology is very promising and has the potential for many exciting uses. With Bluetooth, a handheld device could automatically sync with a personal computer when it gets within range. Internet ports connected to Bluetooth chips would allow handheld users to wirelessly connect to the Internet at high speeds. Bluetooth chips are currently being integrated into newer handheld products and forecasts predict that by 2005, 700 million Bluetooth devices will ship annually. For more information check out: http://www.motorola.com/bluetooth/faq/index.html 802.11b (WLAN): A more robust wireless network that is starting to appear in office buildings and college campuses is the Wireless Local Area Network using the 802.11b standard. Like Bluetooth, 802.11b operate on the 2.5 GHz band, but can achieve transfer rates up to 11 Mb/s at distances 330 meters within the radius of the transmitter. A newer version of the standard, 802.11a is said to transfer at speeds of 54 Mb/s on the 5 GHz spectrum. WLAN connections act just like LAN connections except the connection is wireless. WLAN has been around for a while, but is currently catching on. Even sections of the UMD campus are wired. For more information check out: http://www.cnn.com/2001/TECH/ptech/05/10/what.is.WLAN.idg/index.html CDPD: For greater mobility at the expense of speed is CDPD (Cellular Digital Packet Data). CDPD utilizes existing cellular networks and works very much like a cell phone. Information is sent in packets using the Internet protocol. The benefits of this technology are obvious and much like those of desktop computers, which take advantage of already existing phone lines. The transfer speeds are noticeably slower at 19.2 Kb/s and prices for CDPD modems can run up to $400 not including service plans. Producers of CDPD modems include OmniSky and Novatel, which make models for Palm and PocketPC compatible devices. For more information check out: http://www.novatelwireless.com/company/cdpd.html http://www.gte.com/customersupport/howdoi/cdpd.html