OONO RS232 Breakout Tester LED Monitor Module DB9M/F x DB25M/F, 1 Unit

• RS-232 interface DB9 male, DB9 female, DB25 male and DB25 female, supports any one of the connectors as Master Input, and supports any one of the connectors as Slave Output. Connect in series with any RS-232 interface for testing a serial RS-232 data link. Simple and easy, no oscilloscope is needed. DIP switch can setting disconnect or reconnect any signal, and support external probe test signal from male or female position.
• 8 double-color (red and green) LEDs indicate the logic states for respective data lines. Green for logic HIGH and red for logic LOW. Full RS232 spec compliant with LEDs for all 8 signals: DCD, RXD, TXD, DTR, DSR, RTS, CTS, RI.
• No external power required. No driver required. Plug and play. Jack sockets(nuts) on the tester can be unscrewed easily(with metal shell held in place) if needed to mate with another connector that has jack sockets.
• OS Compatibility: Windows 98, Me, XP, 2000, 2003, CE, Vista, Windows 7, and Windows 8 as well as Linux and Mac OS 10.X, ect.
• Typical application scenarios: Watching the TXD and RXD LEDs either changing states or flashing to know data transferring direction: from machine to computer or from computer to machine. Verifying TXD/RXD wires should be wired crossed(swap pin2 and 3) or straight through by observing TXD and RXD LEDs at a rest state. Verifying it is a DTE or DCE device (and whether you need a null modem or not). Verifying whether modem controls are active, even if they're not being asserted. Testing control sign

• Connect the Tester In-Line — Identify the serial port on your device (e.g., computer, modem, PLC) and the cable connecting to it. Insert the OONO RS232 Breakout Tester module between the device's port and the cable, ensuring the correct male/female connectors are used for master input and slave output.
• Observe LED Indicators — Power on the connected devices. Watch the 8 double-color LEDs on the tester. Green LEDs indicate a logic HIGH state for the corresponding signal (DCD, RXD, TXD, etc.), while Red LEDs indicate a logic LOW state. This provides real-time status of the serial communication.
• Utilize DIP Switch for Signal Control — If needed, use the DIP switch to disconnect or reconnect specific signals for targeted testing. You can also use an external probe to test signals directly from the male or female positions on the tester for detailed analysis.

Typical situations where OONO RS232 Breakout Tester LED Monitor Module DB9M/F x DB25M/F helps — illustrative scenarios, not customer reviews.