Specifications

Appendix C - Glossary of Terms RS-422 And RS-485 Applications Ebook
Page 119 of 137 Manual Documentation Number: <DocNumber>
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RJ-45
A modular telephone style eight-contact connector. Usually male on the
connecting cord, female on devices. The center four positions have contacts
similar to a residential telephone or telephone modem. This is a connector type
only. Devices that use this connector are not necessarily designed for
connection to telephone company phone or data lines. RJ-45 connectors have
been used on some RS-485 systems.
RS-232
RS-232 provides serial connections using single ended signals, which may vary
between -3 to -25 volts to +3 to +25 volts.
Minimal signals for bi-directional communication are signal ground/common,
Transmit (Tx) and Receive (Rx) Data or TD and RD. IBM PC compatible RS-
232C ports provide handshaking lines, DSR and DTR and flow control
handshaking lines, CTS and RTS. Modem control lines for RI (Ring Indicator)
and CD (Carrier Detector) are supported. Data is transferred serially using
Asynchronous data, with a start bit, data bits, stop bit/bits.
Flow control can be performed by software using X-On/X-Off, or by hardware
handshaking if available.
RS-232 Connector
This is the connector used on the RS-232 side of the converter or a RS-232
device. The EIA-232 standard specifies a DB-25 connector but DB-9 connectors
are commonly used.
RS-232 Port
A electrical connector that provides some or all of the RS-232 signal lines.
Unless a device is transmit or receive only, a RS-232 port will provide at least
signal ground/common and RD & TD.
RS-232/RS-422/RS-485 Fiber Optic Conversion
A fiber optical converter which has dual interfaces can be set to convert from
RS-232 to fiber optic at one end and from/to RS-422 or four-wire RS-485 or