急求一篇关于videophone的英语作文!150字即可!

急求一篇关于videophone的英语作文!150字即可!
要求介绍视频电话的功能,特点及使用人群!150字即可,最好写的好一点

A videophone is a telephone which is capable of both audio and video duplex transmission.It differs from videoconferencing in that it expects to serve individuals,not groups.
The widest deployment of video telephony occurs in mobile phones,as nearly all mobile phones supporting UMTS networks work as videophones using an internal camera,and are able to make video calls wirelessly to other UMTS users in the same country or internationally.As of Q2 2007,there are over 131 million UMTS users (and hence potential videophone users),on 134 networks in 59 countries.
Videophones can be used by the deaf to communicate with sign language over a distance.In the US the FCC pays companies for providing Video Relay Service to deaf and hard-of-hearing individuals,where they use a videophone to talk through a sign-language translator to people using audio phones.Videophones are also used to do on-site sign-language translation (Video Remote Interpreting).The relatively low cost and widespread availability of mobile phones with video calling capabilities have given deaf people new possibilities to communicate with the same ease as others,with some wireless operators even starting up free sign language gateways.
Videotelephony is used in large corporate conferencing setups,and is supported by systems such as Cisco CallManager,and similar systems from companies such as Tandberg,Radvision,and Polycom.
Today the principles,if not the precise mechanisms of a videophone are employed by many users world-wide in the form of webcam conferences using personal computers,with cheaply available webcams and microphones and free instant messenger programs.Thus an activity that was disappointing as a separate service found a niche as a minor feature of products intended for other purposes.A videophone can be created by using an old or inexpensive computer and dedicating it to run a video softphone.
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