I have an all in one fax, printer, scanner, copier, coffee maker (just seeing if you all are awake) - and I just use our home phone line to send faxes out and it works well. I've not received any faxes yet, however, I believe it simply picks up if it senses the screech. (Of course I have to test this to be sure.) In order for this to work, I have to be sure that no one answers the phone before the fax has a chance to pick up so I would have to know ahead of time that someone intends to send me a fax. I won't publish my fax number (home number), that way if a client needs to fax me, s/he would have to inquire about it first and then I can outline the procedure.
Eventually, if incoming faxes become an issue, I will invest in a second line specifically for the fax machine ($15/mo via our cable internet phone company)
I did a site search of ehow.com just to see what type of suggestions they have.
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