Cellular phones are produced in extremely high volume when compared to other types of sophistcated portable electronic devices, with over 400 million cellular phones being produced each year worldwide. Digital systems have replaced analog systems in most geographic regions, but global markets have yet to standardize on a single digital system. User expectations for basic handset functionality are fairly stable, but some manufacturers and service providers are working to increase the capabilities of cellular phones to include video telephony, GPS, and PDA-type functionality.

To facilitate our discussion of cellular phones as a class of portable electronic devices, we will examine the Audiovox CDM-8300 tri-mode phone as an example of system design shown in Fig. 8.1. The specifications for this product are listed in Table 8.1. This phone is considered tri-mode because it works on CDMA 1900 networks, CDMA 800 networks, and AMPS (analog) networks. It also has a GPS receiver that enables the phone to determine the GPS coordinates of its location. This product exploits data from GPS satellites and CDMA networks to locate a wireless handset to the accuracy of 5 50 m. The phone is equipped with a charging cradle pictured in Fig. 8.2, which has a two-color LED to indicate charging status. Synchronization of contact data with a PC is possible using a data cable available as an option.

Figure 8.1: Audiovox CDM-8300 Tri-mode phone.