Rabbit EM1500, Руководство по эксплуатации продукта

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Glossary of Terms
RS-232
Full-duplex, electrically single-ended serial interface standard. The electrical and some mechanical
and protocol characteristics of the connection are defined including handshaking lines and a communi-
cations protocol.
RS-485
Half-duplex, differential mode, single driver, multiple receivers serial interface standard.
RTS
Request to Send, a hardware flow control signal driven by a DTE device to tell a DCE device when to
start or stop.
Serial port geometry
This phrase refers to some of the common serial port configuration parameters that must match on
both ends of the connection. They are:
• number of bits per character
• parity
• number of stop bits
These parameters are usually abbreviated; e.g., 8N1 means that there are 8 bits per character, no parity
and 1 stop bit.
SPDT
Single Pole Double Throw, describes a relay that has one pole that can make electrical contact with
two separate stationary contacts; i.e., a normally open (N.O.) contact and a normally closed (N.C.)
contact.
XON/XOFF
This flow control method does not require extra wires. Predefined ASCII values stop (XOFF) and start
(XON) data transmission. This method is only useful for ASCII data, since the XON/XOFF characters
are sent in the data stream and could match bytes in a binary stream.
The byte value of XON is 17 (keyboard entry is Ctrl+Q) and XOFF is 19 (keyboard entry is Ctrl+S).