In the driver for Neets Preamplifier there is only the possiblity to send volume as a value, but it will react to increment and decrement commands as well.
This can be helpful if you are using another control interface than Neets.
The commands are as follows, represented in both ASCII and HEX.
ASCII: NEUNIT=1,VOL=INC<CR> HEX: 4E 45 55 4E 49 54 3D 31 2C 56 4F 4C 3D 49 4E 43 0D
ASCII: NEUNIT=1,VOL=DEC<CR> HEX: 4E 45 55 4E 49 54 3D 31 2C 56 4F 4C 3D 44 45 43 0D
<CR> = Carriage Return