Canon C2050 Service Handbook page 198

SERVICE MODE
COPIER>ADJUST
<DENS>
Use it to enter a developer density signal level.
SGNL-Y/M/C/K
Use it to enter the initial density signal level of the developer.
Settings 0 to 255
Default 0
SIGG-Y/M/C/K
Use it to enter the initial density signal gain level of the developer for ATR
control.
Settings 0 to 255
Default 0
S-56