# 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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.ceruleansonar.com/c/ethernet-rov-locator/communicating-with-the-rovl/serial-parameters.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.