Wi-Fi does not allow you to access the Internet in places where there is no wireless router or hotspot. Consequently, if you want Internet access in areas without a Wi-Fi signal, you need to rely on the 3G and 4G wireless networks used by mobile phone carriers. AirCard is the brand name used by Sierra Wireless for its USB and Express Card wireless modems. However, many users use the term "air card" generically to describe wireless modems from other manufacturers as well. Regardless of what you call the device, purchasing an air card for your laptop will provide you with email and Internet access almost anywhere you go.
Know the Limits
Regardless of which air card you ultimately decide to purchase, you need a wireless data plan to use it. Consequently, before you begin shopping for a wireless modem, you should understand the limits imposed with most data plans associated with the devices. Because of the relatively high cost of bandwidth, unlimited data plans are not nearly as common as they were in the mid-2000s, and most carriers now impose caps on the amount of bandwidth that wireless modem owners can use. Basic data plans under $50 per month usually allow you to download or upload only 2GB to 3GB of data. For heavy users, bandwidth consumption of 12GB to 15GB per month will cost you $100 per month or more. Therefore, if you intend on using your air card in a laptop to watch online movies or to stream music videos from YouTube, a wireless air card may prove to be much more expensive than your home Internet connection.
Depending on the model of your laptop and its age, you may have a couple of options for connecting an air card to your notebook. USB air cards work with virtually all laptops used today, while PCMCIA wireless modems offer a connection alternative to users of legacy laptops or those with no free USB ports. ExpressCard modems are an alternative for USB models for users who don't want to have a dongle protruding from the side of the laptop while carrying it around. The Express Card interface is the modern version of the PCMCIA slot used in older laptops. However, Express Card devices have smaller form factors and fewer pins than do the older PC cards. Express Card modems also use substantially less power. With some lightweight or ultraportable laptops, a USB wireless air card may be your only option, as many smaller notebooks no longer include Express Card or PCMCIA slots. Generally speaking, USB modems are the most versatile. Furthermore, you can use a USB air card with your home or office desktop computer when not using it with your laptop.
3G or 4G
Virtually all modern air cards support the aging 3G wireless technology, and most support some form of 4G connectivity as well. Many nationwide carriers offer 4G networks; however, technologies used by the services to connect to 4G networks vary considerably. For instance, if you want to connect to an AT&T or Verizon 4G network, you'll need an air card or wireless USB modem that supports the LTE protocol. T-Mobile 4G networks require modems that connect using the HSPA+ 42 protocol. Sprint users require different types of modems depending on which branded service they use. Most Sprint subscribers have access to LTE networks. However, if you're a customer of Virgin or Boost -- Sprint subsidiaries -- you may need a modem that supports 4G WiMAX. If you plan to use an air card or wireless modem only occasionally and don't require the fastest type of connection, you may be able to find older, unlocked air cards that support only the older 3G HSPA+ protocols. Most wireless providers still allow access to 3G networks, and while they are not nearly as fast as 4G connections, they are more than fast enough for moderate browsing, chatting and checking email.
Because there are so many competing technologies and protocols associated with emerging 4G networks, the most important factor to consider when purchasing an air card is the service carrier you intend to use. If you already have a wireless phone plan with a carrier, call the company about pricing on USB air cards or wireless modems. In many cases, your service provider may offer you a special deal or promotional price on an air card since you are an existing customer. Even if you don't already have a wireless carrier, the price of USB wireless air cards offered by a company should not be the only factor you consider when shopping. Before choosing a carrier and wireless air card, ask the provider about monthly rates for its data plans as well as the amount of bandwidth the service includes. Ask the service carrier about additional fees if you go over your plan's allotted bandwidth amount for a month. In some cases, the monthly data plan may seem relatively cheap, but if you're a heavy mobile Internet user, your overage charges can easily amount to more than your regular monthly bill if you don't choose the plan carefully.
If you intend to use your wireless air card only in the city or in suburban areas, you shouldn't have many problems connecting the device to your laptop and receiving a relatively strong 4G signal. However, if you plan to use the modem to connect your laptop to the Internet while you're in rural areas, you may want to purchase a USB wireless modem that has a connector for an external antenna. Many modern wireless USB modems have these types of connectors, and the service carrier to which you subscribe or the store where you buy the air card may offers antennas for purchase as accessories. If the service carrier or retailer from which you buy your wireless air card does not have an external antenna for the device, your local electronics store may have them in stock.
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