about line cords for H-P fax machines

The instruction manual and the H-P website warn that "You must use a cable that has only two copper leads" instead of the much more common four-conductor cord. But people have trouble finding them.

We don't know of any technical reason why a fax, or a phone, or any single-line telecom device that normally requires two conductors, would not work just fine with a four-conductor cord, when the extra wires are not connected to anything; but H-P keeps insisting on it.

H-P tech support said that some times the extra two conductors (wires) can act as an antenna and pick up interference that hurts faxing.

I don't understand why Panasonic, Brother, Sharp, NEC and other brands don't worry about it.

However, if your faxing is going gaflooey, and you’re using a four-conductor line cord, there is a chance that the cord is the source of the trouble. So, if you’ve tried everything else, now try the cord that HP recommends. We have 'em.