### Question
What is the definition of TDD?


### Answer
The definition of **TDD** is as follows in *47 U.S.C. § 225*:

> a Telecommunications Device for the Deaf, which is a machine that employs graphic communication in the transmission of coded signals through a wire or radio communication system

#### Citation:
  - *47 U.S.C. § 225*
  - Heading: **CHAPTER 4-RADIO ACT OF 1927 > SUBCHAPTER II-COMMON CARRIERS > Part I-Common Carrier Regulation**

