MSComm does not expose Ring Indicate state (because it was designed to work with a modem, where RI is transient, thus the only indication is via CommEvent = comRingEvent). The only way to read the RI state is via the UART Modem Status Register. You can download IOOcx from my homepage to do this. However, note, that this works only with built-in serial ports, where there is a physical UART.
If you are using a USB serial adapter, then there is no practical way to get the RI status, AFAIK. This "issue" is caused by the way that the serial port device drivers are written, and is historical in nature.
Dick (www.hardandsoftware.net)
Reply With Quote