TTY communication over packet networks
A system to enable TTY communication between a legacy TTY phone and an IP phone over a packet network using a TTY relay protocol established between the IP phone and a media gateway at a central office of the PSTN. The system may also use a voice over Internet Protocol gateway to connect a personal computer to the packet network instead of an IP phone to accomplish TTY communication between software on the computer and a legacy TTY phone.
1. A system for TTY communication over a packet network, comprising:
an Internet Protocol (IP) phone connected to a packet network; and
a TTY phone connected to said packet network through the public service telephone network (PSTN) and a media gateway,
wherein said IP phone and said media gateway establish a TTY relay protocol over said packet network using an out of band session descriptor protocol, and
said IP phone encodes and decodes TTY text characters into a real time protocol (RTP) packet format as text conversation session contents for transmission of the packetized text characters over said packet network.
2. The system of claim 1 , further comprising:
a personal computer, connected to said packet network, to jointly process said packetized text characters with said IP phone.
3. The system of claim 1 , wherein said IP phone and said media gateway transmit said packetized text characters using a standard protocol for TTY character entry by said IP phone and said TTY phone.
4. The system of claim 1 , further comprising:
a personal computer, connected to said IP phone, wherein said personal computer operates a TTY-enabling software for said IP phone.
5. The system of claim 1 , wherein said IP phone and said TTY phone connect a call using said TTY relay protocol.
6. The system of claim 1 , wherein the IP phone and the TTY phone transmit over the packet network without using a special line for TTY transmissions.
7. A system for TTY communication over a packet network, comprising:
a personal computer connected to a packet network through a voice over Internet Protocol (VOIP) gateway; and
a TTY phone connected to said packet network through the public service telephone network (PSTN) and a media gateway;
wherein said VOIP gateway and said media gateway establish a TTY relay protocol over said packet network using an out of band session descriptor protocol, and
said VOIP gateway and said media gateway encode and decode TTY text characters into a real time protocol (RTP) packet format as text conversation session contents for transmission of the packetized text characters over said packet network.
8. The system of claim 7 , further comprising:
an IP phone, connected to said personal computer, to jointly process said packetized text characters.
9. The system of claim 8 , wherein said IP phone and said TTY phone connect a call using said TTY relay protocol.
10. The system of claim 7 , wherein said personal computer and said media gateway transmit said packetized text characters using a standard protocol for TTY character entry.
11. The system of claim 7 , wherein the IP phone and the TTY phone transmit over the packet network without using a special line for TTY transmissions.
12. A method for TTY communication over a packet network, comprising:
connecting a personal computer to a packet network through a voice over Internet Protocol (VOIP) gateway; and
connecting a TTY phone to said packet network through the public service telephone network (PSTN) and a media gateway;
establishing a TTY relay protocol over said packet network, between said VOIP gateway and said media gateway, using an out of band session descriptor protocol; and
encoding and decoding TTY text characters, between said VOIP gateway and said media gateway, into a real time protocol (RTP) packet format as text conversation session contents for transmission of the packetized text characters over said packet network.
13. The system of claim 12 , further comprising:
connecting an IP phone to said personal computer to jointly process said packetized text characters.
14. The system of claim 12 , wherein said personal computer and said media gateway transmit said packetized text characters using a standard protocol for TTY character entry.
15. The system of claim 12 , wherein said IP phone and said TTY phone connect a call using said TTY relay protocol.
16. The method of claim 12 , wherein the establishing further comprises transmitting the RTP packets between the IP phone and the TTY phone over the packet network without using a special line for TTY transmissions.