Captioned Telephone is similar to two-line VCO in that users get the benefit of both voice and text. However, Captioned Telephone uses only one telephone line instead of requiring two, the captions appear at a much faster speed — nearly simultaneously with the spoken words (instead of significantly slower than the speaker). It is far less complicated and cumbersome, and CapTel uses only one device (a CapTel phone) instead of two (a TTY and a Telephone).