6Learning to use your phoneHeadsetsThe M2216ACD-1 has two jacks for electret headsets. You can adjust the headsetinterface, using P, to match the type of headset you are using (See“Program key” on page 5). Contact your sales representative for moreinformation on headset types.The M2216ACD-2, which was manufacture retired in 1995, has a two-hole jack(PJ-327) for a carbon headset and a jack for an electret supervisor headset.You can change the supervisor headset to listen-only or talk-and-listen usingP. See “Headset talk/listen” on page 23The M2216 headset interface has three settings. Until now, those settings havebeen defined as Plantronics, Liberation (GN Netcom) and handset.Headsets vary in electrical, physical and audio characteristics. Performanceperception is subjective so it is recommended that the headset user try using theirheadset with each of the three settings on both internal and external calls todetermine which works best for them. As with all Meridian Digital Telephones,amplified headsets are recommended.