Executive Pro Amplifier (pictured below). 1. Headset / Handset Switch 2. Talk Indicator Light 3. Volume Control (incoming) 4. Mute Switch 5. Microphone Volume Control 6. Battery Compartment 7. DCA Adapter Plug In 8. Handset Jack 9. TEL Jack (Connect To Phone) 10. LA-11 Jack 11. Headset Jack 12. Compatibility Switches Executive Pro Headsets. Executive Pro headsets come in various styles (monaural, binaural and convertible). The headset ends in a quick disconnect clip and routes into Executive Pro (EP) and Executive 3 Elite (E3E) amplifiers via the included quick disconnect to RJ9 modular cord (included with headset). Executive 2 Elite (E2E) users connect via a quick disconnect to 3.5mm adapter cord (PTS/3.5-QD/GREY, sold separately). Executive Pro Though the Executive Pro Series will work with most phones, there are compatibility exceptions. These include AT&T / Lucent / Avaya Partner, Merlin II and BIS models, Nortel Meridian phones with headset jacks, ESI, Panasonic KXT4000B, and Eme…