Specifications

Appendix C - Glossary of Terms RS-422 And RS-485 Applications Ebook
Page 112 of 137 Manual Documentation Number: <DocNumber>
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L
LED
Light Emitting Diode - a semiconductor device that emits light when forward
biased. An LED may be infrared, red, green or yellow. Some package
incorporate two colors. LEDs are often used as a solid state replacement for
bulb indicator lamps. Forward voltage drop is typically 1.9-2.4 volts, making
them suitable indicators when used with a current limiting resistor for low
current TTL indicators or RS-232 signal indicators.
M
Male (Connector)
The connector which has the plug portion or pins which fit a female receptacle
or socket. The plug which inserts into a jack. Usually M after the connector
type indicates a Male connector.
Many products such as printers place the female socket on the device so that if
a pin breaks or is bent on a cable, the cable is more easily replaced than the
connector built-in to a device. The exception is RS-232 serial connectors, which
are male to avoid confusion with the female DB9 video connector and female
DB25 printer connector.
Master (Device)
The master in a network controls all the other devices (slave devices) attached
to the network. The master sends commands to request data, the slaves
respond with data. Some slave devices may prefix their response with an
identifying header.
Master-Slave
A command/response relationship between two devices where one device
sends commands and requests data (Master). The other device only responds
to the commands (Slave), and does not initiate conversation.