G3 internal modem ring sensitivity affects ability to receive faxes?

Bobby Owsinski reports that he is unable to receive faxes with the internal 56K modem that came with his G3 233MT. Sending works, but not receiving. Also, he can receive faxes with an external modem. He writes: "After going around with both STF and Apple, it was determined that the internal modem was indeed at fault. Apparently, the ring sensitivity is set a bit high so if you have a slightly low ring voltage present, the modem doesn't sense it. Apple Customer Service told me that their engineers were aware of the problem."