The cellular option

Novatel's $179 Merlin C201 works in the 1,900-MHz PCS band.

Sierra Wireless' $349 AirCard 750 is an external GSM/GPRS card that supports a variety of standards.

Nokia's D311 combines GPRS and WiFi capabilities in a 4.3-inch removable card.

Cellular PC Cards give you another choice for wireless data transmission

Wireless networking promises connectivity wherever you go. IEEE 802.11b, or WiFi, hot spots are springing up at coffee shops, airports, hotels, government conference rooms and even some McDonald's. According to Gartner Inc. of Stamford, Conn., nearly 20 million wireless LAN devices were sold last year.

But for all its promise, WiFi doesn't really offer untethered computing, just more tethers to choose from. True, you don't have to physically plug in at the hot spot to make a connection, but you are still limited to operating within a hundred yards or so of the wireless access point. That might give you a good excuse to drop by Starbucks, but it does limit your range.
Another option offers greater mobility'cellular data transmission. According to the Cellular Telecommunications and Internet Association of Washington, telecom firms have spent $126 billion over the past two decades establishing their wireless infrastructure. More than 140,000 cell sites now serve close to 150 million subscribers with near-ubiquitous connectivity. The right PC Card for your personal digital assistant or notebook PC can connect you through these same cellular towers to the Internet and your office LAN.

'Wide-area PC Cards make life simple,' Gartner vice president Ken Dulaney said. 'You can use them everywhere.'

The downside, though, is that connection speed is limited and the different cellular service providers have incompatible technologies. In this article we'll take a look at the technologies and some of your options in selecting a card to access these wireless networks.

Although cellular data transmission is a mature technology, it has not really taken off.

'Its use grew last year and is growing this year as coverage becomes more available,' Dulaney said. 'But it is not as big a market as some cell carriers thought it would be.'

Vague figures

Data on exactly how many cellular PC Cards have been sold and the number of subscribers is not readily available. Gartner doesn't have those figures. Ken Smiley, a director of Forrester Research Inc. of Cambridge, Mass., said he tried unsuccessfully to put together some reliable figures last year.

'The carriers won't provide those numbers,' he said. 'If they are not providing the numbers, it generally means that there are not as many as they would like.'

Part of the problem is that the technology is 'nobody's child.' It lies halfway between the fields of IT and telecommunications, but not wholly within either industry. Telecom companies have long focused on voice communications and have been extremely successful at it. Their main approach to cellular data transmission is to add features such as e-mail, photos and Internet browsing to their handsets, rather than worrying about the comparatively small number of data users seeking to connect. They do offer data services, but you won't find it mentioned on their home pages.
The IT community, meanwhile, has its own approach to wireless networking. Administrators are thoroughly versed in the intricacies of TCP/IP and Ethernet, but they are not nearly as familiar with telecom jargon and standards. They are establishing 802.11 wireless LANs in their offices, and it would be easy for them to provide that same type of connectivity for outside access without additional training and with the same end-user equipment.

That also applies to equipment manufacturers. An agency can purchase its switches and routers as well as its WLAN equipment from Cisco Systems Inc. or Nortel Networks Ltd. But cellular PC cards come from companies such as Sierra Wireless Inc. and Novatel Wireless Inc. You can't run down to CompUSA and pick up one of those. In addition, manufacturers of notebooks and PDAs are making WiFi a default feature on their devices.

'Almost every laptop now comes with WLAN built in,' Dulaney said. 'People will want to use it in their houses, their offices and potentially in other environments such as airports.'

But that still doesn't solve the problem of coverage away from those places, which is where cellular connections excel.

To start with, let's look at the competing technologies, which go by the acronyms CDPD, GSM and CDMA.

Cellular Digital Packet Data (CDPD) is a wireless extension of an IP network and is broadly used by emergency services agencies. It transmits data at up to 19.2 Kbps in gaps between voice transmissions. Although CDPD is slower than GSM or CDMA, it currently has the advantage of broader coverage and a lower cost than the other two technologies.

But it might not be the best long-term option. Both AT&T Wireless and Verizon Communications will cease providing CDPD'AT&T in mid-2004 and Verizon at the end of 2005. If you need a data-only solution and widespread coverage is key, then you might want to switch to the data networks of Motient Corp. of Lincolnshire, Ill., or Mobitex from Cingular Wireless of Atlanta. Both cover roughly the 500 most populous cities in the country.

The Global System for Mobile Communications (GSM) family is the next option. This is the system used in Europe and most other parts of the world, and some domestic providers offer it as well.

GSM requires the use of a Subscriber Identity Module'a smart card that plugs into the phone or PC Card and holds the user's account information and custom settings. With a SIM, a person can use any GSM phone and still have access to accounts and custom settings.

GSM has Short Messaging Service for sending text messages of up to 160 characters. The original GSM standard allows data transmission at up to 9.6 Kbps. General Packet Radio Service is an enhancement that raises the transmission rate to 56 Kbps.

Upcoming developments include Enhanced Data GSM Environment, at 384 Kbps, and Universal Mobile Telecommunications Service, at 2 Mbps.

Code Division Multiple Access (CDMA) is the most widely used standard in the United States and is also used in Canada, Central and South America, New Zealand, South Korea, Japan, China, Taiwan and Israel.

The original standard, CDMA One, operated at 14.4 Kbps. The CDMA2000 standard is replacing the original and, according to the CDMA Development Group of Costa Mesa, Calif., had 51 million subscribers worldwide as of May, five times as many as a year earlier.

There are two versions of CDMA2000: 1xRTT, at 144 Kbps, and 1xEV-DO, at 2 Mbps. RTT is widely available in major metropolitan areas in the United States, but EV-DO has yet to be deployed domestically.

Keep in mind, however, that the advertised speeds are not what users can expect. Actual transmission rates run about half those speeds, though many carriers also incorporate a data compression format that boosts the effective throughput. Both the CDMA and GSM groups will eventually attain comparable performance at around 2 Mbps. CDMA currently has the lead.

'The better technology today is CDMA, which is faster,' Gartner's Dulaney said. 'But you may decide to go with GSM/GPRS if you want to use it overseas.'

The cards all follow the Type II PC Card specification and so are physically interchangeable.
'The cards operate the same way,' Forrester's Smiley said. 'If I use a Novatel or a Sierra Wireless card, I can access Verizon and get the same performance.'

There are some differences in the antenna design and power management schemes. Nokia has a card with dual antennas, which lets the user log onto either a GSM/GPRS or a WiFi network.

The main consideration is not the hardware, but whether you can find the access and service you need. Can you log in at the Washington headquarters, the Des Moines branch office and a field inspection site? If you can't get a signal, all those cutting-edge features are worthless.

'What's important is to select the network that best supports your needs in terms of coverage and data bandwidth,' Smiley said. 'Once you have selected the carrier, then you can look at the card itself, but the difference between brands is slight.'

The cellular service providers sell and support some cards for use on their own networks, and Smiley said you should try to get such cards free or at a reduced price, just as with cell phones.
Gartner's Dulaney advised buying a card the provider recommends.

'First pick the provider for the coverage, the speed and the pricing, then buy the card,' he says. 'You can buy any card and it might work, but you really want to buy what the cell provider is supporting.'

Drew Robb of Glendale, Calif., writes about IT.

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