how to turn off fax ringer volume officejet 6700

Can the volume for the fax ringer be silenced or turned off in the hp Officejet 6700 Premium?

The incoming fax line shares the same line as my phone. 

I have turned Off the Fax Sound Volume, which turns off the connecting and dialling sounds, however, I have not been able to turn off the fax ringer.   The fax rings each time that my phone rings and I'd like to stop it.

Any thoughts?