M22 Details: The M22 is designed to work with traditional phones, as well as wideband VoIP phones and phone systems. Newly incorporated “Clearline Technology” offers superior call clarity while providing advanced echo management, consistent and comfortable call volume, reduced background noise and protection against loud sounds. Specs on Wideband: Wideband Technology refers to the audible frequency range for telephony. Traditional telephone systems operate between 300Hz and 3400Hz – Narrowband New telephone systems and VoIP can operate between 150Hz and 6800Hz – Wideband Special Notes on M22 Sleep Mode: When powered by batteries, the M22 enters “Sleep Mode” between calls to prolong battery life. The amplifier/headset will be inactive when you try to take a call. Press either the headset or mute button twice to “wake the amplifier.” The M22 will not enter sleep mode when powered by a DC adapter (part number 26503-01, shown in Figure 1). Clicking (If you are experiencing a clicking soun…