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Definition: EMS


(1) (Enhanced Message Service) An extension to the original cellphone text messaging service (see SMS) that added formatted text, icons, animations and ringtones. Introduced in 2001 by Alcatel, Ericsson, Motorola and Siemens, EMS was superseded by full multimedia support (see MMS).

(2) (Electronic Message Service) The part of the radio spectrum assigned to electronic messaging over digital satellite circuits.

(3) (Electronics Manufacturing Services) A company that makes electronic devices for other companies. See contract manufacturer.

(4) (Enterprise Messaging Server) The original name for Microsoft's Exchange Server. See Microsoft Exchange.

(5) The plural of "em" spacing. See em.

(6) (Expanded Memory Specification) A technique that allowed DOS to reach beyond 1MB of RAM. Introduced in 1985, EMS provided access to 4MB, 8MB and later 32MB of expanded memory by bank switching through a 64KB page frame in the upper memory area between 640K and 1M (see UMA). Users had to specify how much EMS was needed, and applications had to be written for EMS (Lotus 1-2-3, AutoCAD, etc.), or they were run with EMS-compliant software such as DESQview. In IBM PC XTs and ATs, EMS required a board and driver, but 386 PCs could create EMS from extended memory. When Windows came out, it allocated EMS automatically. See DESQview and extended memory.