every constructional feature of Ritchie's patent, he used the exact same fundamental technique, and the analog telautograph principle continued to be used for at least the next 35 years, such as in those installed in the Frick Art Reference Library around 1935, also see . Tiffany patents after 1901 refined the mechanism but not the principle.

Ritchie marketed his design as the Telewriter in the UK. The claim in this last reference that the phone and Ritchie's telautograph could be used simultaneously over the same line is dubious given