Dataradio Gemini PD, Service Manual, Page: 4 / 14

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Definitions
The following terms are used throughout this document.
Item Definition
DCE Data Communications Equipment. This designation defines the direction (input
or output) of the various RS-232C interface signals. Modems are always wired as
DCE. See also DTE.
DTE Data Terminal Equipment. This designation defines the direction (input or out-
put) of the various RS-232C interface signals. Most user equipment, as well as
PCs, are wired as DTE. See also DCE.
GCU Gemini Control Unit board
Gemini/PD High specs mobile radio modem. PD = Parallel decode
HDX Half Duplex. A unit which uses separate transmit and receive frequencies, but
which may not transmit and receive simultaneously.
RS-232 Industry–standard interface for low speed data transfer (EIA-RS-232E).
RSS Radio Service Software. This software allows configuration and testing of the
Gemini/PD.
Simplex A unit which uses the same frequency for transmit and receive.