Motorola A009 communicators use triband technology that allows messaging and cellular telephony while roaming across the global system for mobile communica- tions (GSM) 900, 1800, and 1900 MHz ranges. The communicator also provides personal digital assistant (PDA) capability that features a number of built-in applications, programmability to support third-party applications, and a high- resolution color display. The A009 communicator supports general packet radio service (GPRS) in addition to traditional circuit switched and short message service (SMS) transport technol- ogies. GPRS, where available, provides substantial increases in mobile data com- munications performance and the efficient use of radio spectrum. Data transmission rates for GSM networks can potentially increase from the current rate of 9.6 kbps up to a theoretical maximum of 171.2 kbps. An increased data rate is by no means the only benefit provided by GPRS. A key advantage is the provision of a permanent virtual connection to the network. This "always on" connection is possible because GPRS uses packet data transfer so that, for example, email can be downloaded in "background mode." There is no need for the user to re-connect before requesting a service, eliminating connection set-up delays and adding con- venience and immediacy to data services access. The "virtual" nature of this connection means that network resources are not consumed during periods when a user is not actually sending or receiving data.