It was once easy to distinguish a cellphone: it had a phone number, was used for voice service and offered short message service (SMS) text messaging. Many cellphones also include third-generation (3G) network access to download rich media files and streamed content.

Wi-Fi networks, however, have become more prevalent, the addition of Wi-Fi radios permits hi-speed, low-cost internet access for additional applications on smartphones and other devices. Not only can Wi-Fi service be used for viewing Internet sites, the addition of an appropriate client application transforms a data-centric device into a voice device without using the cellular network.

The presence of multiple network access is a defining feature of the devices that are breaking out of their categories. Among the networks that are finding their way into personal and mobile devices are:

• Cellular in its various forms, including voice networks, as well as UMTS, HSPA and EV-DO data networks.

• Wi-Fi radios that can access business and personal networks, as well as public hotspots and metro-area Wi-Fi systems. Wi-Fi can be used for Internet access, voice over IP (VoIP) using an application such as Skype and for unlicensed mobile access (UMA) of cellular services over a Wi-Fi gateway.

• Broadcast receivers, such as FM radio and mobile video receivers for a variety of video broadcasting technologies, such as ISDBT, DVB-H and MediaFLO are finding their way into cellphones and other devices.

• WiMAX radios are expected to appear in a number of devices, starting with laptop-sized personal computers and eventually appearing in smaller devices.

• GPS provides location data for complex navigation applications, “place stamping” in addition to the traditional time and date stamps, or context for location-based applications, search and content.

• Local connectivity, such as Bluetooth, WiMedia, ZigBee and others, permits devices to send or receive content from other devices. For example, Nokia’s N810 tablet device can access the cellular network using a Bluetooth connection to a cellphone.

Network connectivity is no longer the defining factor in differentiating portable devices. In-Stat expects more devices to connect via multiple networks, so users can be assured of finding access and selecting the preferred network, based on availability, cost, speed or other factors. There is more information about mobile devices and their network connections in “The Revolution in Mobile Devices,” “Impact of Devices on the Mobile Broadband Universe,” “UMDs—Are They for Real? A Worldwide Snapshot” and “Big Trends in Future Cellphones 2007–2012.”