The PL51 PhonePlus telephone amplifier can be left connected when no volume or tone boosting is needed without interfering with the operation of your phone. The Phoneplus turns "on" when the handset is lifted, and it goes "off" when the handset is put back in place.
You'll gain from using our Phoneplus if the sounds of your phone calls are very quiet or muted. If necessary, you can amplify loud or low tones with the Phoneplus and boost the caller's speech level through your handset.
Since the phoneplus may not work with your phone in some circumstances, the PL–51 includes a Handset wiring module that allows you to adjust the settings within the amplifier to make it operate with practically any corded phone.
Sarabec Ltd states that the PL51 telephone amplifier complies with the R&TTE directive 1999/5/EC's essential requirements and other applicable laws.