Need to record your cell conversations? Connect CellTap between the 2.5 mm earpiece jack of your cell phone and your earpiece or headset. Now connect a tape recorder or powered speakers to the 3.5 mm mini jack. This audio output contains a nice mix of both sides of the conversation. CellTap works with any wireless phone that accepts a third party headset or earpiece. Group Listen - Simply connect a powered speaker to the audio output jack and you will have a new conferencing capability. Everyone in the room can hear your conversation, but only the person wearing the headset can talk. While this is not a speakerphone, in many cases it more suitable for sales presentations or contract talks. CellTap must be used with an earpiece or headset. Your cell phone will not recognize CellTap on its own.Does not work with a Blackberry.