I had a customer ask me to h/u a moh to there system. I think it is a definity ATT system. Please forgive (if this is a dumb one) this question. They handed me a 909 module coupler with no power supply, the instuctions say they need a 48volt power supply for it. Do i need to buy one or can i get the power from the ksu/phone system? P.S. requires .10 amp. the system has a rj11 moh input. any help would be great. Thanks