Unless you have a good quality analog phone line from the central office, faxing typically has difficulty these days. I had to order one from the CO for our I.T. department for modem access to routers in case the network went down. We couldn't even use analog lines from our legacy AT&T switch because the T1s are now SIP, converted to 4 wire PRIs. Faxing could and sometimes did work, but not reliably and it was common to have trouble. We have a couple of different efax services that are HIPPA compliant, which is good because much of the faxing is done for medical documents.