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TR41.4/00-11-061 VON_Text_Telephony_GH2

TR41.4/00-11-061 VON_Text_Telephony_GH2. Text Telephony and Total Conversation in the IP revolution Gunnar Hellström, Omnitor AB Gunnar.Hellstrom@omnitor.se +46 8 708 204 288. Accessibility opportunities in IP networks. IP networks take over telecomm traffic Opportunity:

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TR41.4/00-11-061 VON_Text_Telephony_GH2

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  1. TR41.4/00-11-061VON_Text_Telephony_GH2

  2. Text Telephony and Total Conversation in the IP revolutionGunnar Hellström, Omnitor ABGunnar.Hellstrom@omnitor.se+46 8 708 204 288

  3. Accessibility opportunities in IP networks • IP networks take over telecomm traffic • Opportunity: • Combine text, video and voice • Interworking between many ways to access the network • Next generation mobile will have IP capabilities • Important points to consider • Interworking with Textphones in the Telephone Network is desired. • IP Transit for textphones requires special consideration • A simple IP textphone is needed

  4. Total Conversation standards • Text conversation need standards as well as video and audio. • Work is close to completion in ITU-T and IETF to define extension of video telephony to Total Conversation with video, text and voice • Subsets are possible for text telephony

  5. Example of a Total Conversation Terminal Voice Text in video call Sign language Text telephony

  6. Opportunities with Total Conversation • Deaf: sign, type or lip-read as the situation calls for. • Adult deaf: speak and see and get text back. • Hearing impaired – Hear and lip-read as far as possible, revert to text when needed. • Video relay services: Transfer phone number to call • Speech impaired: Hear and type. Or hear and speak and revert to typing when needed. • Anyone: Communicate in preferred mode, type when needed for names, phone numbers etc.

  7. Further opportunities with local additions to Total Conversation • Screen reader and Braille display makes text conversation accessible to deaf-blind users. • Voice recognition can make voice conversation convenient with adult deaf users.

  8. T.140, the common base for text conversation • Standardised in ITU-T 1998 • Extremely simple end-to-end text chat protocol • User input to Unicode UTF-8 coded transmission • UTF-8 transmission to display • Safe and easy to include everywhere User T.140 Channel What is the street address? Alameda 34

  9. T.140 text protocol • Character by character transmission • Character code for any language: ISO 10646 (= Unicode). • Control from ISO 6429: • Erase last character, • New line, • Nelect graphic rendition • Alert in session • Transport channel must be specified for each environment. User application T.140 Channel Network

  10. Text Telephony, a subset of Total Conversation • IP Telephony builds on IP Multimedia technology. • IP Text Telephony builds on IP Total Conversation technology • ITU-T H.323 Annex G Text Conversation and Text SET. IP telephone extension with text • IETF RFC 2793 transport for text in IP networks • Usable in IETF multimedia protocol SIP

  11. Text in IP networks Text in IP networks • H.323 Annex G = text in the dominating IP telephony protocol H.323 • SIP text conversation also possible without further specfikation IP Textphone orTotal Conversation terminal IP textphone Audio(and Video) T.140Text Audio T.140Text RTP RTP RTP RTP IP Network

  12. T.120 Data H.324 H.320 H.324 Text telephony conferencing Mobile system Voice Voice Voice and and and T.140 T.140 T.140 T.140 T.140 video video video AL1 H.245 AL1 H.245 H.224 T.134 T.124 Equal-izers Trans GCC parent H.223 H.221 H.223 T.123 Network Mobile V.18 V.34/V.80 access transmission PSTN ISDN PSTN Total Conversation -a complete family Ready Ready Ready Ready Ready Ready H.323 Voice and T.140 video RTP TCP/ RTP Network access DATA IP MOBILE H.248 Annex F. Text - aware Gateway For decision in ITU 13 Nov. 2000

  13. V.18 An automoding modem - a bridge to mono media textCan be used in gateways and servers Example of use USA, UK USA Holland Germany France Anywhere Sweden, UK

  14. Text telephone interworking • T.140 is also used in standardised text telephony. • V.18 enables communication with a huge number of existing text telephones T.140 T.140 equalizers for legacy modes T.140 ready transmission in V.18 mode V.18 text telephone modem

  15. PSTN Interworking • Gateways need to have V.18 capabilities, to connect PSTN text telephone calls with Total Conversation or IP Text Telephone terminals • Gateways need to be T.140 aware T.140 text in IPchannel V.18 compa- tible text V.18/T.140 PSTN Textphone Gateway H.323Annex G T.140 alternating with voice RTP/Audio Gateway example V.18 - H.323

  16. Textphone gateway call between Telephone network and IP network

  17. Textphone call in telephone network passing through IP network

  18. IP gateway standardisationITU-T H.248 and IETF Megaco • Current hot topic – huge efforts. • Text telephone and text conversation additions. • Integration of text – fax – modem additions • Possible use – same port for voice, text, fax and modem, automatic identification of mode and invocation of proper packetization.

  19. Conclusions • Video telephony is complemented with text to form Total Conversation • Text Telephony is linked in through a standardised bridge – V.18 • Work is centered in ITU-T SG 16 with Q9-Accessibility as initiator • Many companies and organisation have contributed • Standards are in place, implementations emerge

  20. Standards support for Total Conversation and text telephony F.MCVS Service Description Text conversation T.140 Text, video and voice (PSTN) H.324 Text telephony (PSTN) V.18 Data conferencing T.120, T.134 Gateway H.248 Text, video and voice ISDN- H.320 H.224 Mobile textH.324M Text, video and voice (IP) H.323 Annex GRTP-Text

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