By Peter Rysavy  Wide-Area Wireless Computing Hardware In selecting wireless hardware, you need to consider form factor, power consumption, cost and hardware compatibility. Form Factor First-generation wireless modems were somewhat bulky and heavy. For example, the Mobidem modem for the RAM Mobile Data network weighed more than 1 pound. But today you can purchase PC Card modems (Type 2 or Type 3) for most wireless data networks. Some of these are fully integrated; others use a short cable to an RF module. Most use their own battery. If you are integrating a wireless modem into a product, you will find that many wireless modem vendors offer OEM modules designed specifically for vertical market applications. Power Consumption and Battery Life Most wireless modems today draw power from a battery, though some are powered by the mobile computer. Wireless modems typically transmit in the 100 mW to 1 W range. Because the amount of power that needs to be supplied by the battery can be almost five times higher than the actual transmission power, the battery life of a wireless modem is typically limited to a day of normal use. Test the battery life of the modems you are considering for your application, and keep in mind that transmitting data consumes significantly more power than receiving. Cost Wireless modems are complex electronic devices, containing interface logic and circuitry, sophisticated radios, considerable central processing power and digital signal processing. As such, they cost more than landline modems. Most wireless WAN modems cost $500 or more. If using a cellular connection, all you need is a PC Card modem that supports cellular protocols, such as MNP10 or ETC, and a compatible cellular telephone. Hardware Compatibility If using an external modem, your connection will probably be a serial connection, and you should not experience any compatibility issues. If you are using a PC Card modem, make sure you test your modem and mobile computer together. You could run into a compatibility problem related to radio frequency interference, heat or power fluctuations. Introduction Planning Protocols and Interfaces Hardware Wireless Middleware Profile of Wireless Networks Integration Updated September 30, 1997 Print This Page E-mail this URL