Question: can rj45 be used for telephone?
Answer: RJ11 Phone to RJ45 Jack. Cat5, Cat5e, Cat6 cable is frequently used for wiring telephone jacks. You can send up to 4 telephone lines on one 4 pair cable that terminates at a RJ45 (8P8C) jack. The problem is most phones, even multi-line phones, don't directly plug into an RJ45 jack.