sign and are harder to test than synchronous chips. As clock speeds grow faster, more and more time and energy are spent on the clock function, asynchronous chips may break into the processor market, especially for cellular telephones. Here are some of their advantages over standard synchronous chips: They use less power. They run faster. They generate less heat. They do not generate the radio frequency (RF) interference generated by quartz-crystal timers. Their encryption is harder to break because in synchronous chips the timer is a clue that can be used by decoding devices. The Philips pager with an asynchronous processor had twice the powered-on operat- ing life of its competitors. Philips created the initiative to make, test, and produce these chips so that it could continue to develop them for cellular telephones and other markets. At the time of publication, no other manufacturer has asynchronous chips in production, although IBM, Intel, and other companies have created them in their laboratories. There is also a role for continued size reduction, but it depends on customer accep- tance of the technology. At present, wrist cell phones, worn like a watch, are a novelty. However, if mobile telephones attached to the body become popular, we will see a fur- ther drive toward miniaturization. The first steps in that miniaturization are already occurring. Some users prefer an invisible headset with a phone attached to a small belt clip. In addition, voice-activated dialing is now a common feature. If the keypad is re- placed by voice-activated controls, then battery size once again becomes the key driver in the move toward miniaturization. This demand would then drive battery technology even more rapidly in the direction of increased power at smaller sizes. 8 Call quality is clearly a driver in the adoption of cellular systems and a significant reason why customers prefer CDMA to AMPS in the United States. In the development of mobile telephones, the quality of the radio is a factor in the quality and capacity o