Modem 6 sends and receives data using MDFT (modem data frame transfer). MDFT is Sonardyne’s overall acoustic protocol for transferring data, used in Modem 6 products. Data is split into frames prior to transmission across the acoustic link, it is then reassembled at the other end before being outputted to the user.

What is the maximum MDFT frame size?

The maximum frame size (denoted here in terms of user payload) depends on the selected telemetry scheme.
• TS1 has a maximum frame size of 1,376 bytes
• TS2 has a maximum frame size of 2,656 bytes
• TS3 has a maximum frame size of 5,728 bytes
• TS4 has a maximum frame size of 27,488 bytes
• TS5 has a maximum frame size of 55,136 bytes
• TS6 has a maximum frame size of 30,048 bytes
• TS7 has a maximum frame size of 83,808 bytes

What if my payload is more than the maximum MDFT frame size?

In Fire and Forget mode the Modem 6 will continue to transfer the remaining data as long as the previous frame was successfully transferred. In Acknowledged mode the MDFT command reply will indicate that more data is available and another MDFT transfer can be scheduled to collect the remaining data.