Product specifications

COMMUNICATIONS
Sharp Electronics Corporation
Glossary - More on RS232
Independent channels are established for two-way (full-duplex) communications. The
RS232 signals are represented by voltage levels with respect to a system common (power /
logic ground). The "idle" state (MARK) has the signal level negative with respect to
common, and the "active" state (SPACE) has the signal level positive with respect to
common. RS232 has numerous handshaking lines (primarily used with modems), and also
specifies a communications protocol.
The RS-232 interface presupposes a common ground between the DTE and DCE. This is a
reasonable assumption when a short cable connects the DTE to the DCE, but with longer
lines and connections between devices that may be on different electrical busses with
different grounds, this may not be true.
RS232 Term Definitions
Glossary of Abbreviations, etc.
CTS Clear To Send [DCE --> DTE]
DCD Data Carrier Detected (Tone from a modem) [DCE --> DTE]
DCE Data Communications Equipment e.g. Modem
DSR Data Set Ready [DCE --> DTE]
DSRS Data Signal Rate Selector [DCE --> DTE] (Not commonly used)
DTE Data Terminal Equipment e.g. computer, printer
DTR Data Terminal Ready [DTE --> DCE]
FG Frame Ground (screen or chassis)
NC No Connection
RCk Receiver (external) Clock input
RI Ring Indicator (ringing tone detected)
RTS Ready To Send [DTE --> DCE]
RxD Received Data [DCE --> DTE]
SG Signal Ground
SCTS Secondary Clear To Send [DCE --> DTE]
SDCD Secondary Data Carrier Detected (Tone from a modem) [DCE --> DTE]
SRTS Secondary Ready To Send [DTE --> DCE]
SRxD Secondary Received Data [DCE --> DTE]
STxD Secondary Transmitted Data [DTE --> DTE]
TxD Transmitted Data [DTE --> DTE]
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