diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt
index a493238..c8878f8 100644
--- a/Documentation/serial/serial-rs485.txt
+++ b/Documentation/serial/serial-rs485.txt
@@ -104,6 +104,9 @@
 	rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
 	rs485conf.delay_rts_after_send = ...;
 
+	/* Set this flag if you want to receive data even whilst sending data */
+	rs485conf.flags |= SER_RS485_RX_DURING_TX;
+
 	if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) {
 		/* Error handling. See errno. */
 	}