Serial Port Pin-Out for SAGE RTU 2400

Issue:

Users need the correct pin-out configuration for the DB-9 serial ports on the SAGE RTU 2400 for connecting external devices or troubleshooting communication issues.

Product:

SAGE RTU 2400

Environment:

• SAGE RTU 2400 Baseboard
• Optional C3438 RS-232 Port Card
• SCADA communication setup using RS-232 serial ports

Cause:

Incorrect wiring or misunderstanding of the DB-9 connector pin assignments can lead to communication failures between the RTU and external devices such as IEDs, MTUs, or modems.

Resolution:

The SAGE RTU 2400 baseboard provides five serial ports:

• UIF Port (dedicated for PPP or Console)
• Ports 1–4 (for communication with IEDs, MTUs, or redundant channels)
  Additional ports (up to 12 total) can be added using C3437/C3438 expansion cards.

DB-9 Pin-Out Configuration:

For basic RS-232 communication, only pins 2 (RXD), 3 (TXD), and 5 (GND) are required. Other pins are used for modem control and synchronous connections.

LED indicators on the baseboard show activity for DCD, RX, RTS, TX, CTS for each channel.

Released for: Schneider Electric Singapore