• • Deafness
Terminals that can display sign language or permit lip-reading will be especially valuable for users with severe hearing difficulties. The definition and frame update rate on PSTN (Public Switch Telephone Network) connected videophones are not currently adequate for this usage. Sign language has its own grammar and syntax and is regarded as a language in its own right, so those who use it may regard written English (ie. text) as foreign. This group of users, which includes many of those who were born deaf, will not be well served by the Telephone network until high definition video Telephony is readily available.
