why while talking on the phone after a minute the tone of the fax goes on and the sound is so loud that i cannot talk on the phone anymore?
Do you have "call-waiting" service? If so, then a second caller has called you, while you are talking to the first caller. So, if you do not "flash" to that caller, your FAX machine "answers" the second caller.
It is a "race" -- the FAX machine counts the number of rings before answering, and, if you subscribe to Shaw voice-mail, it is also counting the number of rings before answering and then collecting a voice-mail message. Which ever "counter" reaches its limit first will be the one to answer. In your case, the FAX is "winning", so it answers, and "screeches" at you.
Can you reprogram the FAX to reduce the sound-level of those "screeches" ?
Do you have "distinctive ring", so that the FAX machine recognizes the alternate "ring" sound, and answers?