Feb 2004 Table of Contents

COMPUTERS

A Primer on Wireless Networks



FREE PREVIEW Log in or buy this issue to read the full article. AAFP members and paid subscribers get free access to all articles. Subscribe now.


FREE PREVIEW Subscribe or buy this issue. AAFP members and paid subscribers get free access to all articles.

A wireless network can give you the freedom to access your EMR on a laptop, PDA or tablet PC.

Fam Pract Manag. 2004 Feb;11(2):69.

This content conforms to AAFP CME criteria. See FPM CME Quiz.

Many family physicians are jumping on the electronic medical record (EMR) bandwagon, having recognized that an EMR system has the potential to increase efficiency, enhance revenue and reduce errors. An EMR system requires a network that will allow multiple computers to share data and communicate through a local server or a remote server over the Internet. If you want to avoid the hassles of hard-wiring your office (or you have a building-use contract that doesn’t allow it) or if you prefer the freedom of using a portable PC, such as a laptop, personal digital assistant (PDA) or tablet PC to access your EMR, you will need to establish a wireless network in your office. And even if you don’t have an EMR, this type of network can be used to allow multiple computers in your practice to access a central file server and/or the Internet without running cables.

WANs, LANs and WLANs

To understand how wireless networks function, you first have to understand some networking basics. There are two major types of networks – a wide area network (WAN), which is open to users and hackers alike (e.g., the Internet), and a local area network (LAN), which is a closed, private network of computers (e.g., an office with one large server and many computers and printers). LANs may be connected to WANs to facilitate access to the Internet. A “firewall” helps prevent outside intrusion into a network and can also be used to prevent LAN users from accessing the Internet.

Hardwired networks rely on wiring called “Ethernet” to physically connect computers. Standard Ethernet (10Base-T) allows data transmission at speeds up to 10 megabits per second (mbs), which is more than 175 times as fast as accessing the Internet with a 56K modem. Newer, faster versions of Ethernet are also available (100Base-T at 100 mbs).

Wireless networks (WLANs), which transmit data over radio waves, are comparable in speed to Ethernet. Among WLANs, there are several “protocols,” or versions, available that allow wireless transmission of data at varying rates and distances. The first protocol, 802.11b, transmits data at a frequency of 2.4 ghz for up to 300 feet at speeds theoretically up to 11 mbs. The second protocol, 802.11a, has the ability to modify the transmission rate (bandwidth) inversely with distance at a frequency of 5.0 ghz. This allows for faster speeds up to 54 mbs but shorter ranges of 50 feet to 75 feet. The third and latest protocol, 802.11g, combines elements of both of the earlier protocols with a 2.4 ghz frequency and transmission between 27 mbs and 54 mbs for up to distances of about 300 feet. These WLAN protocols have popularly become known as “Wi-Fi.”

Creating a wireless network

Establishing a WLAN for a home or small practice is fairly straightforward and relatively inexpensive when compared with other EMR costs; it’s somewhat more complicated for larger practices. Unless your group includes a physician who’s especially computer savvy, you’ll probably need to hire an outside consultant to set up the network. You’ll need to hard-wire a wireless router to the server. The router, which is a small box with a transmitting antenna, costs about $100. It converts the data from the server into a radio signal in the 802.11 standard. Some offices may also require several boosters, which cost about $100 each, to prevent “dropout,” which is a periodic loss of network connection.

Unless you have a newer computer that’s Wi-Fi ready, you’ll need to have a card installed on your computer to enable it to receive the Wi-Fi signal. The card must be designed for a standard (a, b, g or b/g) that is compatible with the router, and your computer must be within range of the router (the ranges for each protocol vary, as described in the previous section). These cards usually cost between $50 and $100.

Note that wireless routers do not in themselves provide access to the Internet. For Internet access, the router needs to be connected to the Internet via a DSL or cable modem.

Once you have all the hardware installed, you’ll also need to install software (which comes with the router and/or card) on your computer to activate the network and select security settings. Some manufacturers of wireless networking products enable you to do this through a Web-based service.

Security issues

Wireless networks are inherently susceptible to security breaches. In fact, it is fairly easy for a savvy hacker to locate an unprotected wireless network and exploit it to access the Internet, or worse, to access private files. Fortunately, several security features are available that can make hacking into wireless networks nearly impossible. For example, most routers have built-in firewalls that offer protection from would-be invaders, and many systems use WEP (wired equivalent privacy) 128-bit encryption, which offers robust security of transmitted data by automatic coded scrambling and unscrambling. In addition to these often built-in features, there are a number of simple things wireless network users can do for more protection:

  • Turn the broadcasting feature off. Most routers allow for active “broadcasting” of their existence so that anyone can easily join the network, and by default, many routers have this feature turned on.

  • Change the default network name and password. These are usually known to hackers and are often left unchanged by users.

  • Allow access to identifiable MAC (media access control) addresses only. Every wireless device has a unique ID called a MAC address. You can set the WLAN to only allow access to devices with known MAC addresses, which will make it much harder for hackers with random MAC addresses to gain access.

In addition to taking steps to protect your wireless network from intrusion, you should consider using a Virtual Private Network (VPN) to transmit or access sensitive material via the Internet. VPNs use encryption and authentication to allow secure point-to-point transmission of data between private networks.

Final words

Although setting up a WLAN is fairly easy, it may be advantageous to seek the help of a consultant or networking expert initially. This person can help you choose a system that is best for your office space and then maximize its level of security. Whatever wireless networking system you choose will give you the amazing ability to walk from room to room with a portable computer and access the server and Internet untethered.

Dr. Lewis practices in Lawrence, Kan., and uses a WLAN with 802.11g.

Conflicts of interest: none reported.

Send comments to fpmedit@aafp.org.


Copyright © 2004 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact fpmserv@aafp.org for copyright questions and/or permission requests.

Want to use this article elsewhere? Get Permissions


Article Tools

  • Print page
  • Share this page
  • FPM CME Quiz

Information From Industry