> For the complete documentation index, see [llms.txt](https://docs.ceruleansonar.com/c/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ceruleansonar.com/c/ethernet-rov-locator/communicating-with-the-rovl/serial-parameters.md).

# Serial Parameters

All receivers/transceivers support TTL-level serial communication at 115,200 baud, 8 bits, no parity, one stop bit. These parameters also hold if the unit is set to use its USB interface and the proper USB cable is used.

All Transmitters with firmware prior to July 1, 2021 operate at 115,200 baud, 8 bits, no parity, one stop bit. Mk II transmitters with firmware after July 1, 2021 operate at 9600,N,8,1 if the autosync option is installed and 115,200 baud, 8 bits, no parity, one stop bit if not autosync.  Mk III transponders operate at 115,200 baud, 8 bits, no parity, one stop bit.