Sony SRF-DR2000 Operating Instructions Manual page 27

Select the desired symbol group by pressing the
Function buttons corresponding to ↑ UP or ↓ DWN. To
activate the symbol group, press the Function button
corresponding to ON. To deactivate the symbol group,
press the Function button corresponding to OFF.
Note
Deactivating a symbol group will not only disable reception of data
for the symbols in the group, but recollection of data stored in the
memory for this group as well. This will not, however, clear the
stored data.
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