128Accessories for the M3900 Series telephonesFull Duplex Hands Free ModuleThe Full Duplex Hands Free Module provides simultaneous audio paths fortransmitting and receiving during hands free calls. The Full Duplex HandsfreeModule is available for the M3904.HeadsetsAmplified headsets are compatible with your M3900 Series Meridian DigitalTelephone. The amplified headset is an option for noisy environments. Anamplified headset should be connected to the handset jack. The Headset Key isnot able to control a headset that is connected to the handset jack. In thisconfiguration, do not select Headset as the On hook default path.For an amplified headset, adjust the volume using the Volume Control Bar onyour telephone before adjusting the volume on your headset amplifier. Tominimize distortion, the volume setting on the amplifier should be higher than thevolume setting on the telephone.Unamplified headsets are compatible with the M3903 and M3904. Anunamplified headset should be plugged into the headset jack. With Headsetselected as the On hook default path, you can make calls or answer incomingcalls by pressing a DN Key.For an unamplified headset, access Volume Adjustment in the Options List toadjust the headset volume and sidetone (M3904) that work best with the headsetyou are using. You may also use the Volume Control Bar to adjust the headsetvolume while you are on a call.Refer to your distributor for the latest productbulletin from Nortel Networks for recommended headset types for the M3900Series telephones.Key-based Expansion ModuleThe Key-based Expansion Module provides additional line (DN) or feature keysfor the M3904. You can add up to two Key-based Expansion Modules, for a totalof 44 additional line (DN) or feature keys.Personal Directory PC UtilityThe Personal Directory PC Utility provides a faster, easier way to create or modifythe Personal Directory on the M3904. You can enter names and numbers into adirectory file on your PC, and download the file directly from the PC to the M3904through a serial port connection. You can also upload the Personal Directory fromthe M3904 to your PC so that you can modify the directory. The PC and theM3904 are connected using the Personal Directory PC Utility Cartridge. TheComputer Telephony Integration Adapter (CTIA) may also be used to connect thePC and the M3904 when used with the optional Personal Directory PC Utilitysoftware.
