Sharp UX-470 Operation Manual page 62

Remote Operations
OGM only mode
To turn on OGM only mode, press "1",
"1", and "#". (Your outgoing message
will play, but callers will not be able to
record a message. Faxes sent by
automatic dialling will be received).
To turn off OGM only mode, press
"1", "2", and "#".
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1 1
1 2