Increased e-mail and messaging usage coupled with inexpensive wireless devices and company-specific mobile applications will be factors in building the North American wireless subscriber base to 137.5 million users by 2005, a new study released Wednesday concludes.

Circuit-switched data service was the leading technology type used by subscribers in 2000, employed by 38 per cent of the 7.3 million wireless data subscribers, according to the study from Dataquest Inc., a unit of Gartner Inc. Sprint PCS Group and Verizon Wireless Inc. pushed the service as a means of gaining wireless Web customers, the study states.

By 2005, however, 70 per cent of wireless data subscribers will use cellular packet data networks, Dataquest said. A primary reason is that packet networks offer customers an always-on capability, the San Jose, Calif.-based research firm said. With this move to greater wireless adoption, mobile handsets will continue to lead in the numbers of access devices, but PDAs (Personal Digital Assistants) will gain in popularity, Dataquest said.

Mobile device improvements like larger displays, improved input capabilities and sleeker form factors will increase usability and assist with further adoption, said Michael King, senior industry analyst for Dataquest’s Telecommunications and Networking group, in a statement.

Dataquest, a unit of Gartner Inc., in San Jose, Calif., can be reached at