Environmental Control technically refers to heaters and air conditioners while EADLs put the emphasis on what daily living tasks are being accomplished, such as independence in telephone use, home entry and exit and leisure activities. Low Tech systems provide limited control of only one or two devices. A switch can control a battery operated or electrical device directly, in latch or in timed modes.
Direct control requires the switch to be held down for the device to operate.
Latch control requires one switch hit for on and another hit for off, like your light switch. Timed control allows the device to continue running for a preset amount of time after a single switch hit. Toys, tape players, Christmas tree lights, train sets, and popcorn poppers are some favorite devices that can be controlled by Low Tech EADLs. High Tech systems provide more sophisticated control of a variety ofdevices. Most direct and switch based EADLs require reading, though several switch based systems now have auditory scanning and speech feedback.