Know with this LED mini tester
This RS-232 mini tester is designed to connect in series with any RS-232
interface. Bright red or green LED signals clearly show which lines are active.
The LEDs’ color indicates Negative or Positive voltage, with red meaning
Negative, green showing Positive.
Mini Testers are used to check the interface for failures and to help identify
the equipment that has failed. The tester may be left in the line permanently.
It is transparent to data transfer.
Seven LED’s indicate the status of the following lines: TD, RD, RTS, CTS,
DSR, DTR, and CD. Model 9PMTT has male and female DB9 connectors.
Dimensions: 2.0 x 2.14 x .63 in (5.0 x 5.4 x 1.6 cm)
RS-232 Connections That Work - Connecting Devices or Converters
 Diagram - DTE or DCE?
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Servers
Diagram - DTE or DCE?
