| Option 11c Maintenance Terminal and modem 30f9 is talking about the model number to the amplifier for the headset, not the model number for the phone. And that is right, there is a cover that slides off the side next to the battery compartment, if I remember correctly, it should be set to 4 or 5 to work with the 2616 and there is a small volume adjustment just to the right of that. OR, the batteries may need changing! Good Luck! |