Dual modern architecture to support the transfer of non-Baudot TTY telephone calls

• US 8,031,842 B1
• Filed: 07/05/2006
• Issued: 10/04/2011
• Est. Priority Date: 07/05/2006
• Status: Active Grant

• Current Assignee: Avaya Incorporated
• Original Assignee: Avaya Incorporated
• Inventors: Windhausen, Richard A., Michaelis, Paul Roller
• Primary Examiner(s): Ramakrishnaiah; Melur
• Application Number:
  US11/482,027
• Time in Patent Office: 1,917 Days
• Field of Search: 379/52, 379/45, 379/265.02, 379/265.09, 379/90.01, 379/93.01, 379/93.05, 379/93.07, 379/93.17, 379/93.23, 379/93.26, 379/93.35, 379/93.32, 379/93.34, 455/404, 455/3.06
• US Class Current: 379/52
• CPC Class Codes: H04M 3/42391 where the subscribers are hearing-impaired persons, e.g. telephone devices for the deaf

Abstract

A telecommunications system 100 is provided that includes a plurality of TTY devices 124a-n, a switching system 104 to switch a call to a selected one of the plurality of TTY devices; and back-to-back modems 132a-m comprising first and second modems 136 and 140. The first modem 136 faces the TTY devices 124a-n and the second modem 140 faces a set of outgoing trunks.

Claims

1. A communication method, comprising:

a first modem receiving a first carrier tone-based text stream from a first TTY device, the first carrier tone-based text stream being defined by a first transmission protocol;

the first modem converting the first carrier tone-based text stream into a data stream, the data stream being defined by a second transmission protocol different from the first transmission protocol;

the first modem transmitting the data stream to a second modem;

the second modem converting the data stream to a second carrier tone-based text stream, the second carrier tone-based text stream being defined by the first transmission protocol;

transmitting the second carrier tone-based text stream to a second TTY device, wherein the first and second TTY devices are connected, via the first and second modems, to effect a phone call between a first user of the first TTY device and a second user of the second TTY device, wherein the first and second modems are part of a common enterprise network, wherein the second transmission protocol is not carrier tone-based, wherein the carrier tone between the first TTY device and first modem is interrupted during a selected time interval; and

during the selected time interval, the second modem maintaining a continuous carrier tone with the second TTY device.

2. The method of claim 1, wherein the first and second TTY devices are ASCII modems, wherein the first and second modems are back-to-back modems, and wherein the first modem is inward-facing towards the first TTY device and the second modem is outward-facing towards the second TTY device.

3. The method of claim 1, wherein the carrier tone between the first TTY device and first modem is interrupted by at least one of a call transfer, a call hold, or other similar telephony feature.

4. The method of claim 3, wherein, after the carrier tone is interrupted and during the time interval, the carrier tone is re-established between the first TTY device and first modem.

5. The method of claim 3, wherein the carrier tone is interrupted by a call transfer and further comprising:

a switching system, in response to receiving a call transfer request from the first user, commanding the second modem to perform the step of maintaining a continuous carrier tone.

6. The method of claim 3, wherein the carrier tone is interrupted by a call hold and further comprising:

a switching system, in response to receiving a call hold request from the first user, commanding the second modem to perform the step of maintaining a continuous carrier tone.

7. The method of claim 6, wherein a memory of at least one of the first and second modems comprises a set of predetermined TTY messages and further comprising:

the switching system, in response to receipt of the hold request, commanding the at least one of the first and second modems and/or a modem controller to forward a selected one of the predetermined TTY messages to the second TTY device.

8. The method of claim 3, further comprising, after the time interval:

a switching system receiving a call disconnect signal; and

the switching system commanding the second modem to interrupt the carrier tone between the second modem and the second TTY device.

9. The method of claim 1, further comprising:

a switching system receiving, from the first TTY device, a dialed number of the second TTY device;

the second modem performing a handshake with the second TTY device;

the second modem signaling the first modem to initiate a handshake with the first TTY device; and

the first modem initiating a handshake with the first TTY device to complete the call.

10. The method of claim 1, wherein the first modem, in a first mode, generates a text stream in accordance with the first transmission protocol and in a second mode generates a text stream in accordance with the Baudot protocol, wherein the first modem is in the second mode, and further comprising:

the second TTY device transmitting a third carrier tone-based stream to the second modem;

the second modem converting the third carrier tone-based stream into a second data stream;

the second modem transmitting the second data stream to the first modem; and

the first modem converting the second data stream into at least one of Dual Tone Multi-Frequency or DTMF and Baudot codes.