rootâ² canal` ther`apy. n. 1. the branch of endodontics that treats disease of the dental pulp. 2. a treatment for such disease in which the pulp is removed and replaced by filling material.
A textphone is a device that enables phone calls to be made using text. Textphone software can be used on a computer to enable it to be used as a textphone.
A landline telephone is connected by a pair of wires to the telephone network, while a mobile phone, such as a cellular phone (which first became commercially available in the early 1980s) is portable and communicates with the telephone network by radio transmissions.ntil approximately the 1970s most telephones used a rotary dial, which was superseded by the modern DTMF push-button dial, first introduced to the public by AT&T in 1963. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation.