There is little option with many landline phones to move away from noise sources. Phones located in loud spots, a car repair shop for example, can use a little extra boost, as can the home phone of a person with hearing impairment. Amplification can be added through auxiliary equipment, existing phone features or devices dedicated to providing louder, and clearer, sound.
An affordable and portable solution to landline amplification, handset amplifiers connect between the phone body and the telephone handset. The handset's modular telephone connector is unplugged from the phone body, then into the handset amp, which in turn connects to the phone body. Controls include volume and tone, with some models providing microphone muting with a button press to reduce background noise. ClearSounds, Clarity and Serene Innovations each manufacture handset amplifiers. This design is compatible with single and multi-line phones, in any application using corded handsets.
No longer exclusive to the business world, speaker phones have integrated amplifiers capable of providing sound at a much higher volume than standard handsets. Not only is the louder volume helpful for listening, a user now receives sound through both ears, which aids both clarity and comprehension. Consumer landline phones with both corded and wireless handsets can be found with speakerphone capability from companies such as Uniden, Panasonic and VTech.
Products for hearing-impaired users naturally include amplifiers and often noise reduction and tone control as well. Models such as the ClearSounds WCSC600 use digital audio-signal processing to permit fine-tuning of the phone's sound as well as adding up to 50 decibels of additional volume. Most makers of phones for the hearing impaired offer wireless handset landline models that incorporate additional amplification, such as Clarity's D700 series and Serene Innovations' CL-30 and CL-60 models.
Hybrid devices that assist amplifiers provide additional solutions for telephone communications. Bluetooth connectivity, in particular, bridges the gap between technologies. Landline phones, such as the ClearSounds iConnect, permit calls through a cell phone, using Bluetooth connection to the landline phone for conducting the call. ClearCaptions is a federally-funded near-real time closed captioning system for hearing impaired people that, through a phone such as the Ensemble from Clarity, provides captioned phone calls.