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Universal TTY/TDD devices for robust text and data transmission via PSTN and cellular phone networks

  • US 6,611,804 B1
  • Filed: 12/06/2000
  • Issued: 08/26/2003
  • Est. Priority Date: 06/15/1999
  • Status: Expired due to Term
First Claim
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1. A device for transmitting text messages in a communications system, comprising:

  • a first modem that supports at least one of the transmission protocols covered by ITU-T V.18; and

    a second modem that supports a new protocol having at least one of a) a higher reliability than the transmission protocols covered by ITU-T V.18, for connections that include digital cellular networks; and

    b) a bit transmission rate higher than 50 bits per second.

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