Cadac M16 - Manual (Page 46)

APP-8
M16 Microphone Amplifier Revision MA2005-7
M16 Software Version
To check the software/firmware version of the M16 make sure that
no PFL switches are enabled and simulteneously press and hold the
Inc, Dec and Rev buttons on the front panel. The version numbers
will be displayed for both the M16 control software and the MADI
firmware.
The +18dB LEDs indicate the MADI firmware version while the -
36dB LEDs indicate the control firmware version. In both cases the
16 LEDs across the front panel display two 8-bit binary numbers with
the Most Significant Bit to the left. This display allows the firmware
versions to be read as v.vv.
The example below shows a MADI version of 1.01 and the control
software revision of 1.02.