ITU/TDD modem - Patent Review 5905476

Claims

What is claimed is:

1. A computer system that can communicate with a remote device across a communication line for receiving, transmitting, and displaying textual characters, comprising:

a modem for communicating with the remote device; and

a computer having a display screen and an electrical connection to the modem whereby the computer can communicate with the remote device, the computer including software that formats the textual characters into a vertical split screen having vertical areas on the display screen, wherein textual characters from the computer are displayed in one vertical area and textual characters from the remote device are displayed in another vertical area, and wherein the computer software instructs the modem to transmit and receive control characters with the remote device to synchronize protocol settings with the remote device thereby providing compatible operation and synchronization of the textual characters between the vertical areas, and wherein the textual characters of one vertical area are synchronized with the textual characters of the other vertical area to thereby reflect the real time transmission of the textual characters and maintain the relative timing of the communication between the computer system and the remote device, and wherein in the event of simultaneous communication the computer maintains the textual characters of one vertical area substantially in line with the textual characters of the other vertical area.

2. The computer system of claim 1, wherein the computer includes a memory and wherein the textual characters are stored in the memory for later recall on the display screen in substantially the same format as originally displayed on the display screen.

3. The computer system of claim 1, wherein the textual characters are transmittable to a printer in electrical communication with the computer and wherein the printer produces a printout of the textual characters in substantially the same format as displayed on the display screen.

4. The computer system of claim 1, wherein the modem is in communication with a plurality of remote devices and wherein the computer includes software for formatting the textual characters from the computer and each remote device into a respective vertical area on the display screen, and wherein the textual characters of each vertical area are synchronized to reflect the real time transmission of the textual characters and maintain the relative timing of the communication between the computer system and the remote devices.

5. The computer system of claim 4, wherein the software maintains the textual characters of each vertical area substantially in line with the textual characters of the other vertical areas to maintain the relative timing of the communication between the computer system and the remote devices.

6. The computer system of claim 4, wherein the computer includes a memory and wherein the textual characters are storable to the memory for later recall on the display screen in substantially the same format as originally displayed on the display screen.

7. The computer system of claim 4, wherein the textual characters are transmittable to a printer in electrical communication with the computer and wherein the printer produces a printout of the textual characters in substantially the same format as displayed on the display screen.

8. The computer system of claim 1, wherein the control characters are not displayed on the display screen.

9. A computer system for communicating between a local and remote location for receiving, transmitting, and displaying textual characters, the computer system, comprising:

a local modem;

a remote modem connected through a communication line to the local modem;

a local computer electrically connected to the local modem and including a local display screen;

a remote computer electrically connected to the remote modem and including a remote display screen, whereby the local and remote computers may communicate through the local and remote modems; and

the local and remote computers including software that formats the textual characters into vertical areas on the local and remote display screens, wherein textual characters from the local computer are displayed in one vertical area and textual characters from the remote computer is displayed in another vertical area, and wherein the local modem and the remote modem transmit and receive control characters with one another to synchronize protocol settings and thereby provide compatible operation and synchronization of the textual characters between the vertical areas, and wherein the textual characters of one vertical area are synchronized with the textual characters of the other vertical area to thereby reflect the real time transmission of the textual characters and maintain the relative timing of the communication between the local and remote computers, and wherein in the event of simultaneous communication the software of the local and remote computers maintains the textual characters of one vertical area substantially in line with the textual characters of the other vertical area.

10. The computer system of claim 9, wherein the computer system includes a memory and wherein the textual characters are stored to the memory for later recall to display the textual characters on the display screens in substantially the same format as originally displayed on the display screens.

11. The computer system of claim 9, wherein the textual characters are transmittable to a printer in electrical communication with the computer system and wherein the printer produces a printout of the textual characters in substantially the same format as displayed on the display screens.

12. The computer system of claim 9, further comprising:

at least one additional remote modem connected through the communication line to the local modem and remote modem;

an additional remote computer electrically connected to the at least one additional remote modem and including an additional remote display screen, whereby the additional remote computer may communicate through the additional remote modem; and

the local and remote computers including software that formats the textual characters from the local and remote computers into separate vertical areas on the local and remote display screens, and wherein the textual characters of each vertical area are synchronized with the textual characters of the other vertical areas to thereby reflect the real time transmission of the textual characters and maintain the relative timing of the communication between the local and remote computers.

13. The computer system of claim 12, wherein the software of the local and remote computers maintains the textual characters of each vertical area substantially in line with the textual characters of the other vertical areas to maintain the relative timing of the communication between the computer system and the remote devices.

14. The computer system of claim 9, wherein the control characters are not displayed on the local display screen and the remote display screen.

15. A computer-readable medium whose contents cause a computer system to communicate with a remote device across a communication line for receiving, transmitting, and displaying textual characters by performing the steps of:

forming a connection between the computer system and the remote device to allow transmission and reception of textual characters;

formatting a display screen of the computer system into a vertical split screen having vertical areas on the display screen, wherein textual characters generated from the computer system are displayed in one vertical area and textual characters received from the remote device are displayed in another vertical area; and

synchronizing the textual characters of one vertical area with the textual characters of the other vertical area to thereby reflect the real time generation of the textual characters and maintain the relative timing of the communication between the computer system and the remote device.

16. The computer-readable medium of claim 15, whose contents cause a computer system to further perform the step of:

maintaining the textual characters of one vertical area substantially in line with the textual characters of the other vertical area in the event of simultaneous communication to maintain the relative timing of the communication between the computer system and the remote device.

17. The computer-readable medium of claim 15, whose contents cause a computer system to further perform the steps of:

storing the generated textual characters of the computer system and the remote device in a memory of the computer system for later recall; and

displaying the textual characters on the display screen in substantially the same format as originally displayed on the display screen.

18. The computer-readable medium of claim 15 whose contents cause a computer system to further perform the steps of:

transmitting the textual characters to a printer in electrical communication with the computer system; and

producing a printout from the printer of the textual characters in substantially the same format as originally displayed on the display screen.

19. The computer-readable medium of claim 15 whose contents cause a computer system to further perform the steps of:

generating control characters;

transmitting the control characters to the remote device; and

processing received control characters from the remote device, wherein the control characters synchronize protocol settings between the computer system and the remote device to thereby provide compatible operation and synchronization of the textual characters between the vertical areas.

20. The computer-readable medium of claim 19 whose contents cause a computer system to further perform the step of:

preventing the display of the control characters on the display screen of the computer system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ITU/TDD/VOICE modem and, more particularly, an ITU/TDD/VOICE modem that may operate in a stand alone mode, which includes an answering machine mode and a prestored outgoing message mode.

2. State of the Art

The telephone system or "public switched telephone network" (PSTN) was first developed in the late 1800's to allow for person to person communications by voice over long distances. The invention of computers made it useful to exchange digital data over the PSTN. In the 1950's, "modems" were developed for that purpose. A modem accepts digital data, modulates it into a form suitable for transmission over the PSTN such that a corresponding receiving modem can demodulate the signal back into the original digital data.

Modems provide a means for the deaf or speech impaired to communicate over the telephone system, since typed characters can be sent over the PSTN via modem and read by another modem user. However, standard modems have evolved with poor provision for communications by the deaf or speech impaired and are largely unsuitable for this purpose. Standard modems were developed primarily for computer to computer communications. For example, most standard modems have a "carrier" which is a constant audible signal. If this signal is lost because the call is placed on hold, a standard modem will generally hang up and cannot reestablish the connection with a different modem. Modems are very inflexible in their protocol requirements and will not operate properly or will abort the call if the protocol settings are wrong.

In the late 1960's, three deaf engineers developed a new type of very simple modem called a TDD or "telecommunication device for the deaf", sometimes called a TTY. A TDD is typically a stand alone modem system with an integral keyboard and display that allows typed characters to be exchanged with another TDD over the PSTN. Because of its simple protocol requirements, the TDD is robust and easy to use. Consequently, the TDD is, in many respects, more suitable than are standard modems for communications by the deaf.

The International Telecommunications Union ("ITU") (formerly known as the CCITT) has been active in setting various modulation standards for modems. Examples of ITU standards are V.21, V.22, V.22 Bis, V.32, V.32 Bis, and V.34. In the United States, prior to the adoption of ITU standards, various "Bell standards" were established. Examples of Bell standards are Bell 103 and Bell 212. As used herein, an "ITU modem" is a modem that may operate using an ITU modulation/demodulation protocol (or standard). Typically, ITU modems may also operate in at least one Bell modulation/demodulation protocol. A "Bell modem" may operate in a Bell modulation/demodulation protocol. Most modems currently being sold in the United States are ITU modems that are capable of transmitting and receiving in various ITU modulation/demodulation protocols as well as Bell modulation/demodulation protocols. The term "ASCII modem" is sometimes used to refer to an ITU or Bell modem.

As used herein, a "standard modem" is a modem other than a TDD that follows an established protocol such as an ITU or Bell modulation/demodulation protocol and transmits and/or receives data over a communication medium. The communication medium may be a telephone system (such as the PSTN), private branch exchange (PBX), or other media such as microwave link, coax, or fiber optic cable. ITU modems and Bell modems are examples of standard modems.

Differences between standard modems and TDDs include: (1) TDDs encode text characters with the generally obsolete five bit Baudot code, while most modems and desktop computers in the United States today use an ASCII encoding, also known as the ANSI X3.4-1977 or ASCII-77 encoding, (2) TDDs do not provide for parity bits, (3) TDD's in the United States transmit/receive only at 45.45 bits per second, and (4) TDDs use frequency shift keying modulation/demodulation at frequencies of 1400 and 1800 Hz. Because TDDs do not use ITU modulation and protocol schemes, TDDs and ITU modems are incompatible and cannot communicate with each other.

Dual purpose modems have been developed that can communicate with both TDDs and ITU modems. Some of these dual purpose modems have the capability to determine whether incoming and outgoings signals are in TDD format or standard modem format.

SUMMARY OF THE INVENTION

A modem system includes an ITU/TDD/VOICE modem or other modem that is connected to a local computer and a telephone line. The ITU/TDD/VOICE modem allows transmission and reception of ITU, TDD, and voice signals over the telephone line to and from a remote device (such as a remote TDD, ITU modem, or telephone). The modem system according to the present invention may include one or more of the following features. The modem system may be used in a network whereby an indicator on a display screen indicates sound energy received by the modem over the line. The modem system may allow speed jumps from one speed to another during a call. The modem system includes a display in which the screen is split into two vertical areas, to display text sent between remote computers. The text sent by one computer is displayed in the right vertical area, while the text of the other computer is displayed in the left area. The vertical placement of the texts are based on the relative time in which they were sent to the other person. The modem system may also provide a special provision for 300 BPS connections, voice recognition, typing during a file transfer, and prevention of file transfers and/or high speed transfers. Certain aspects of these features are described in detail in the specification below. A local modem may communicate control information to a remote modem to, for example, synchronize protocol settings.

An embodiment of the present invention includes an ITU/TDD/VOICE modem that is connected to a communications medium (such as a telephone line) and is connected to or internal to a local computer. The ITU/TDD/VOICE modem allows transmission and reception of ITU, TDD, and voice signals over the telephone line to and from a remote device. Examples of remote devices include a remote TDD and a remote ITU modem (which typically connects to or is internal to a remote computer). The ITU/TDD/VOICE modem may operate in various modes including (1) a computer communications mode and (2) a stand alone mode. During computer communications mode, the ITU/TDD/VOICE modem is controlled by the local computer. During stand alone mode, the ITU/TDD/VOICE modem operates independently of the local computer. The stand alone mode may further include an answering machine mode and/or a prestored outgoing message mode.

Under other embodiments of the invention, the ITU/TDD/VOICE modem or modem system includes various other features including one or more of the following which are described in detail in the specification: a particular utilization of the transmit/receive LED's in TDD mode; the ability to reacquire a new ITU or TDD connection from TDD mode (i.e., reacquisition mode); techniques for minimizing answer tone duration; techniques for modem status query; techniques for silencing Baudot or ITU modulation during voice carry over or hearing carry over; and uses for audio-in and audio-out connectors.

Different embodiments of the invention may include some but not others of the various modes and features described herein. The various modes and features may be employed in various combinations. For example, ITU modem that does not have TDD capabilities, may include answering machine mode, prestored outgoing message mode, and other features described herein. An ITU/TDD modem need not include voice capabilities. An ITU/VOICE modem need not include TDD capabilities. Facsimile capability may be included with any combination.

Various features described herein may be used independent of a TDD modem. For example, the split screen feature may be used between two modems (which may or may not be ITU modems) without any involvement with a TDD modem.

Various other aspects of the invention are described below.

The claims as originally filed or later added define the scope of the invention. Accordingly, if a feature described herein is not included in a particular claim, that claim should not be construed to include that feature