Source:http://linkedlifedata.com/resource/umls/id/C0183298
UMD: Systems designed to summon help through the telephone system by people who are unable to dial a telephone. These systems usually consist of a portable wireless radiofrequency transmitter and a receiver console that are connected to the telephone system. Typically, the user wears the transmitter around the neck, on a belt, or on a wrist; pressing a button initiates the system's response sequence. The system may be activated by people who cannot operate the standard transmitter button using other means, including pressure bars that are located on the forearm and that can be pressed with the chin; breath-activated transmitters are also available. Personal emergency response systems (PERSs) are available in two types: programmed calling PERSs designated to alert responders (e.g., neighbors, relatives, emergency personnel) directly and monitored PERSs that call an emergency response center that in turn communicates with the responders. PERSs are used mainly by the elderly and others with chronic illnesses or