HP LaserJet Enterprise 500 MFP M525 - Manual (Page 164)

Menu item Description
Detect Dial Tone The Detect Dial Tone setting determines whether the fax checks for a dial tone
before sending a fax.
Dialing Prefix The Dialing Prefix setting allows you to enter a prefix number (such as a "9" to
access an outside line) when dialing. This prefix number is automatically added to
all phone numbers when dialed.
150 Chapter 8 Fax ENWW