The Center of Rehabilitation Engineering (CERTEC) in Lund, Sweden has combined a PDA, digital camera, satellite navigation receiver, and cellular phone into a device intended to help people who are lost find their way. The device, called Isaac, permits users to telephone a support center for directions and, using the digital camera, photograph their surroundings to show support center personnel where they are - using the cellular link to relay the photos. If more precision is needed, there's a global positioning navigation system capable of plotting the lost person's location within a few hundred meters. Isaac was designed for the "differently abled", people who have cognitive dysfunctions, CERTEC says. But it has broader applications in forest surveillance and other venues that require sophisticated navigation skills. Isaac comes packaged in a special carrying case with a power supply and three antennae. [Datamation, 10/01/95, p26]