Wireless Telephones

Wireless telephones are hand-held phones with built-in antennas, often called cell, mobile, or PCS phones. These phones are popular with callers because they can be carried easily from place to place.

Wireless telephones are two-way radios. When you talk into a wireless telephone, it picks up your voice and converts the sound to radiofrequency energy (or radio waves). The radio waves travel through the air until they reach a receiver at a nearby base station. The base station then sends your call through the telephone network until it reaches the person you are calling.

When you receive a call on your wireless telephone, the message travels through the telephone network until it reaches a base station close to your wireless phone. Then the base station sends out radio waves that are detected by a receiver in your telephone, where the signals are changed back into the sound of a voice.

The Federal Communications Commission (FCC) and the Food and Drug Administration (FDA) each regulate wireless telephones. FCC ensures that all wireless phones sold in the United States follow safety guidelines that limit radiofrequency (RF) energy. FDA monitors the health effects of wireless telephones. Each agency has the authority to take action if a wireless phone produces hazardous levels of RF energy.

Hands-free kits can be used with wireless phones for convenience and comfort. These systems reduce the absorption of RF energy in the head because the phone, which is the source of the RF emissions, will not be placed against the head. On the other hand, if the phone is mounted against the waist or other part of the body during use, then that part of the body will absorb more RF energy. Wireless phones marketed in the U.S. are required to meet safety requirements regardless of whether they are used against the head or against the body. Either configuration should result in compliance with the safety limit.

Since there are no known risks from exposure to RF emissions from wireless phones, there is no reason to believe that accessories that claim to shield the head from those emissions reduce risks. Some products that claim to shield the user from RF absorption use special phone cases, while others involve nothing more than a metallic accessory attached to the phone. Studies have shown that these products generally do not work as advertised. Unlike "hand-free" kits, these so-called "shields" may interfere with proper operation of the phone. The phone may be forced to boost its power to compensate, leading to an increase in RF absorption. In February 2002, the Federal trade Commission (FTC) charged two companies that sold devices that claimed to protect wireless phone users from radiation with making false and unsubstantiated claims. According to FTC, these defendants lacked a reasonable basis to substantiate their claim.