I think you will also need to supply a battery to the phone. The phone system battery is -48v (with the audio riding on it). Not sure how low a voltage will work. Try different standard batteries. When you hear the message, your good.
I think you will also need to supply a battery to the phone. The phone system battery is -48v (with the audio riding on it). Not sure how low a voltage will work. Try different standard batteries. When you hear the message, your good.