This modification allows the SBE9plus CTD to accept an RS-232C serial instrument data stream and transmit to the surface.
The acceptable baud rate at the SBE9plus CTD is determined by the EPROM version installed in the modem board. These modem board options include, 9600 or 19200 baud, 8 bit data, and “none” parity. At the surface the SBE11 deck unit will extract the serial data from the standard telemetry and transmit data to a remote host PC/computer via a DB-9 connector on the back panel of the deck unit. This data is transmitted to the host computer at 19200 baud regardless of the serial instrument baud rate at the underwater unit.
The SBE 911plus system was designed with idea that all 9plus would operate with all 11plus deck units. With the modification for serial uplink, however, only a modified 9plus will work with a modified 11plus.