You don't use broadband to send a fax all you need to do is to plug the fax lead from the HP device into a filtered telephone socket on the broadband line (just like any telephone) and it should work fine. Incoming fax will be received on the number for the telephone line you have used.
Don't know the HP7130 but I have an HP 2610 multifunction as I believe the functionality is the same. You can use it to send faxes manually using the keypad on the device. There is also settings in the device options to change the number of rings for a fax before the machine answers. You can also set it to manualy answer if you prefer. Should all be in the manual click here