Why Isn't My SerialPort DataReceived Event Firing?

Troubleshooting SerialPort Data Reception Issues

This guide addresses a common problem: the DataReceived event of a SerialPort object failing to fire. Despite correct code, the event remains unresponsive.

The core issue often stems from incorrect serial port handshake settings. Using Handshake.None prevents the system from asserting the Data Terminal Ready (DTR) and Request To Send (RTS) signals, essential for communication with many serial devices. This effectively tells the device your system isn't ready, halting data transmission and preventing the DataReceived event from triggering.

The solution is to adjust the handshake configuration. Handshake.RequestToSend is generally a suitable replacement for most scenarios. Here's the corrected code snippet:

<code class="language-csharp">ComPort.Handshake = Handshake.RequestToSend;</code>

After making this change, verify your serial port parameters (port name, baud rate, data bits, parity, stop bits) are accurately configured. Tools like PuTTY or HyperTerminal can help confirm these settings.

If problems persist, consider using a diagnostic utility such as SysInternals' PortMon to analyze driver behavior and pinpoint deeper issues hindering communication.

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