WO1993020647A1

WO1993020647A1 - Data communication device___________________________________

Info

Publication number: WO1993020647A1
Application number: PCT/GB1993/000677
Authority: WO
Inventors: Christopher Donald Sibthorpe Moss
Original assignee: Moss Christopher Donald Sibtho
Priority date: 1992-04-01
Filing date: 1993-04-01
Publication date: 1993-10-14
Also published as: GB9207186D0

Abstract

A self contained data communication device intended for use in receiving and forwarding analog or digital messages including voice, fax and/or digital data and which includes a controlling microprocessor (18) a RAM memory (10) for buffer storage, an external connection (4) for a telephone line, and local connections (14, 16) for fax and computer devices. When receiving, the device identifies the nature of an incoming message from a header attached by a similar device which is transmitting (or alternatively by the absence of such a header) and switches itself into a suitable mode in which it can store the message in digital form, initially converting it from analog form if necessary.

Description

"Data Communication Device"

This invention relates to data and voice communication devices, and in particular to a unit which is adapted to both send and receive communications in the form of analog signals such as voice, as well as digitally coded information such as facsimile and computer encoded messages.

Various types of combined analog/digital communication devices are currently available, for use in conjunction with an ordinary telephone line, and (for example) , a computer, fax machine, or telephone. Some devices of this kind are adapted to automatically switch between "data" and "analog" modes, on receipt of an incoming signal, so as to make a connection between the telephone line and the appropriate receiving device, such as a computer in the case of an incoming digitally coded text message, or a fax machine in the case of an encoded image signal. However, most known devices of this kind have the disadvantage that one or more suitable receiving devices must be "on-line" to receive the incoming information, otherwise it will be lost. Furthermore, in the case of communications such as fax or computer (modem) communications, it is generally necessary to have a separate device for each type of outgoing communication, such as a dedicated fax machine including its own modem, and a separate modem for computer data communications, or alternatively, a specially designed "fax/modem" card which must be installed in an expansion slot of the computer.

Accordingly, the present invention seeks to provide a unit which combines a number of the above functions, in such a way as to "free-up" other equipment so that it is not required to be permanently connected to a telephone line, or left waiting in a "host mode". Accordingly, the present invention provides a data communication device, including means for connection to a communication line, and at least one connection means for external analog or digital message input and output; means for converting analog messages to digital form, buffer storage means for storing incoming and/or outgoing messages, and control means adapted to control the storage and forwarding of the said messages in both directions.

It will be understood that the term "message" is used generally herein to denote any kind of information bearing signal.

In addition the device may incorporate means for encryption/decryption of messages so as to enable source communication links to be established.

Preferably, the device incorporates a conventional telephone function, including a key pad and display, and a hand set to enable direct handling of voice messages.

Alternatively the device incorporates a socket into which a conventional telephone can be connected.

In a preferred form of the invention, the connection for communications comprises a standard telephone line connection, and the connection means for other devices include serial and/or parallel ports for connection of devices such as a fax machine and a computer.

The message storage means preferably comprises a RAM memory and may also include magnetic tape or other mechanical storage devices, in order to expand its capacity.

It will be understood that the expression "analog to digital conversio ^"means" is intended to encompass devices which operate in both D/A and A/D modes, and the functions of the device in the case of the present invention preferably include the functions of determining what type of connection is being made using the standard "dual tone multi-frequency" signalling system, and converting voice waveforms to digital signals (codec) .

Preferably the type of connection to be made is determined by DTMF transmission and detection. There are number of possible variations depending on whether the device is sending or receiving and whether it is using voic or fax/modem. The aim is to make multiple use of the phone acceptable even without the benefit of ISDN (Integrated Service Data Network) support, though the provision of ISDN makes it no less useful because of its storage and switchin functions.

Preferably, the control means for the device includes a microprocessor and a "ROM" program memory.

One embodiment of the invention will now be described by way of example, with reference to the accompanying drawing, which is a schematic block diagram of a device in accordance with the invention.

The overall control of the device is achieved by microprocessor 18 and a control program in ROM 20.

The component (2) marked "D/A converter" has thre particular functions which operate bidirectionally:

1. Initiating and monitoring the call connection.

2. Determining what type of connection is being made using the standard DTMF (Dual Tone Multi Frequency) signalling system (see below) .

3. Converting voice waveforms to digital signals (codec) .

These functions are realised in one or more existing chip designs. ^~~

The method by which messages are received and transmitted via the telephone socket (4) is described first; then the methods of recovering the messages and placing the in the machine for transmission.

When the device answers an incoming call (either on user pickup or after a specified number of rings) it will regularly issue a single DTMF code via the modem clip (6) (probably chosen from the ABCD group of tones) whether the telephone user picks up the phone or it is answered automatically by the device. It then listens to the line to detect if there is a data transmission coming in. If it is on auto-answer it transmits a regular answerphone-like message.

There are then five possible courses which the conversation can pursue: a. Another similar machine is calling, or a regular fax, modem or teletex machine that is capable of transmitting a DTMF signal. This will transmit a tone, or series of tones (an example of which is given in Appendix

A) , that establish the type of transmission required using a non-negotiable offer and acceptance or rejection. (This is necessary because the range of possible modes cannot be inferred simply from a carrier in a reasonable length of time) . The device will then instruct the modem (6) to generate tones of the appropriate standard (Fax group 3, v32.bis, v21 etc) b. A fax, modem or telex machine is calling which does not understand the system. In this case the modem can be preset to recognise one of several standard tones and respond in a less reliable way but one which allows the user to receive the regular messages they expect. c. A person is calling to leave a voice or other message, and is in possession of a touch-tone phone. They can shortcircuit the. answer message by pressing one of the buttons on their machine, and either leave a message, instruct the phone to call back or possibly pick up an alternative pre-recorded message. d. A person is calling who is not aware of the system. In this case it acts like a standard answerphone. e. A short message using DTMF tones or a control function is received. This may be for instance a call-back request, a request for a certain type of information, a "bleeper" message or a message to a home remote control system.

In the case that a person has picked up the telephone receiver in the device, the machine may continue to listen for recognised tones. If it detects them it will request the user to replace the handset (via the display (8) and/or a tone) and continue as above.

It should be noted that there is in general no need for incoming messages to have any known identification or routing information. The message might contain such information, to provide distribution capability on to internal computer networks for example, but any such routin will normally be done outside of the device. However the device may optionally incorporate some method of encrypting and decrpting messages to improve the security of the message transfer.

Outgoing messages placed in the memory (10) of th machine paired with the phone number or numbers to which they are to be sent, entered via keypad 12, may be sent immediately or at some preset time.

The device attempts to place the call in the normal fashion (respecting relevant statutes for redialling delays etc.) and when it has finished dialling it listens t the line to detect the call completion. What happens then depends both on the type of message and the response. a. Voice message destined for a named individual. When the connection is made and answered by a person, the device transmits a introductory message which says somethin like "I have a message for if they can receive the call then please hit button 7 on your touchphone immediately". When this response is received, the system will the invite them to press another button to initiate the message, but it will also wait for a longer period before disconnecting. If it does not hear the tone, or hears a tone indicating cancellation, then it will disconnect in a shorter period. b. Fax, modem or voice message to another similar device, or to a computer directly connected to the line, when the device hears the DTMF tone at the other end, it responds with the correct tones and then initiates the transmission. c. The device has a fax or modem message and is answered by a conventional fax or modem device, then transmission is sent as far as is possible using the standard protocols. d. The device has a modem message and is answered by a conventional fax machine. It converts the modem message into a raster image (this may be done in advance and stored) and transmits the message or fax message. Other conversions, such as text to voice by synthesiser, voice to text by voice recognition and image to text via OCR are also envisaged though the conversion may need to be performed outside of the device. e. It is also possible to use the DTMF tones themselves to transmit a short electronically coded message. This is useful for communicating with some extant pagers and mobile phones or for short messages intended to be displayed on another Messenger.

The other part of the device is the local communication which is generally desynchronised (though the size of buffer and period of delay may both be almost reduced to zero) . The aim of the device is to make it a general purpose device that can be connected to a number of different input and output devices that are in common use, so that the user can obtain the required utilility in an economical fashion. The device therefore typically contains at least two serial or parallel ports 14, 16, and a telephone handset or equivalent for voice messages.

These functions may be divided into reception and labelling of a message for transmission and reception and disposal of incoming messages. Since the i/o devices are themselves separate from the device, these lists are not intended to be exhaustive, but simply to show the intrinsic capabilities of the device.

A number of input devices may be linked to the device to generate outgoing messages. a. A microphone for input of voice messages, generally through a conventional telephone handset (including the provision of suitable identification) . b. The inbuilt keypad (12) , which can be used to enter telephone numbers and also short messages for transmission. c. A fax-type scanner which can convert a page into a series of greyscale pixels. (A conventional fax machine may be used if it has a suitable interface.) d. A conventional keyboard connected via a serial or parallel line. e. A computer (or any other device) which transmits complete messages to the device using a serial or parallel interface. The format of these messages is not determined by the device except inasfar as it is necessary to determine (1) the destination of the message (2) the length or ending of the message. It can therefore include any digitally encoded information. However if the start of the message conforms to the X400 standard for electronic messages, then the header will be scanned to detect the destination of the message, which will be either a telephone number or possibly a name whose telephone number is already stored in the device's memory, and perhaps a transmission time. Outgoing messages may be labelled or unlabelled. The label consist of the form of the message, a telephone number and a time delay, together with a identification number. Messages are held until they are properly labelled.

The following output devices are envisaged: a. An inbuilt speaker which can transmit voice messages and possibly text messages via a synthesiser. b. A small display which is used for displaying the labels of received messages and also for showing the first lines and perhaps the whole of text, graphic or fax messages. c. A conventional printer. Generally suitable messages may be sent to a printer as soon as they are available. Subsequently the message may or may not be deleted from the device's storage. d. A computer connected to one of the serial or parallel ports. When the device is connected and has information to send, it may transmit regular signals to the computer until it responds to say that it is ready to receive data. It then transmits one or more messages, using a conventional format such as that stipulated by the X.400 protocol. The messages may be text, graphics or sounds. In the case of received messages that already have X.400 headers these are transmitted faithfully, though the device may not itself have any dispatch functions for internal networks. e. Some secondary storage device. f. A home control system than can activate floodlights, turn on the central heating etc.

In normal functioning, the despatch of messages in both directions is automatic. When a message has been transmitted satisfactorily and an acknowledgement received, the message can be deleted if storage space is required for other purposes. The transmission and reception lists can also be changed directly using the device's keypad (with suitable security provisions) .

In addition to the reception and transmission functions, the device can also have a number of ancillary functions, such as identification, the storage of telephone directories, maintenance of transmission and receipt records, accounting of telephone charges and archiving of messages.

It will thus be appreciated that the preferred form of device can perform the following functions: a. Store messages in both incoming and outgoing directions; b. Handle voice, fax and other digitally coded messages; and c. Work with conventional telephone exchanges as well as ISDN exchanges.

It may be used in conjunction with a fax scanner and printer, a small or large computer or alone, and by providing a storage facility, it relieves these other potentially less reliable and more expensive devices from constant use. By providing compatibility with the three most commonly used modes of information transmission (voice, fax and modulated digital encoded signals) it enables the use of any these existing services to send message to, and receive message from, the device over a telephone line.

In the case of use of the device with ISDN in which there is an extra control channel in addition to the data channels, header information identifying the type of message may of course be carried on that line. In order to avoid loss of the information when it passes through non ISDN exchanges/network areas, however, a version of the header information may also be carried with the data on the data channel. In systems where data conforms to Electronic Data Interchange standards, the header information may also carry an indication of this.

It will also be appreciated that the particular embodiment of the device which has been described it purely exemplary, and, for example, could be realised at various different levels of integration.

Appendix A. DTMF Protocol.

The dual tones are referred to using the conventional 1-9,0,*,#.A-D for the 16 possible tones. It will be noted that all codes are terminated by # to provide expansion capability without need for any delay.

A Messenger is ready and waiting for a signal.

* A voice or DTMF message follows. This is followed by one of the following codes.

1 Record a voice message

2 Accept the following tones up to # as a call-back phone number

3 Accept the following tones up to # as a DTMF alphabetically coded message

4 Replay a recorded message whose number is indicated by the tones following up to #

5 Same as B code below (but may be disabled)

6 Same as C code below (but may be disabled)

7 Accept the following tones up to # as an alternative request (whose nature is not specified further here).

In case 1 the messenger will respond within a short time period to indicate its readiness to accept a message.

B A fax message follows. This is followed by one of the following codes to indicate the protocol to be used 1# Group 1 2# Group 2 3# Group 3 4# Group 4

The response of the Messenger is to generate the appropriate modulation tone and sign-on signal for that class of fax.

C A modulated coded message follows.This is followed by one of the following codes to

D This code is left undefined for future expansion.

# When used by itself, this indicates that the sender is ready to accept a signal

Claims

1. A data communication device comprising first means (4) for connection to an external communication line, and second means (14. 16) for local input and output of an l , and/or digital messages; means (2) for converting analog messages to digital form, buffer storage means (10) for storing incoming messages from the communication line and/or outgoing messages from the local input, and control means (18, 20) adapted to control the storage and forwarding of said messages in both directions.

2. A device according to claim 1 further comprising a telephone type handset, and a keypad for data entry.

3. A device according to claim 1 or claim 2 further comprising display means.

4. A device according to any preceding claim further comprising standard telephone line connection means, and serial and/or parallel ports for connection of a fax machine and/or a computer or other local input/output device.

5. A device according to any preceding claim in which the buffer storage means includes a RAM memory.

6. A device according to any preceding claim further comprising means for storing-data on magnetic tape or disc.

7. A device according to any preceding claim including means for detecting and monitoring an incoming call to determine whether it comprises analog or digital data and converting analog data if detected, to digital data for storage.

8. A method of transmitting and receiving messages o different forms which may include analog voice, digital image, digital data or other analog or digital messages, th method comprising attaching an identifying header to the message before transmission, decoding the header on receipt of the message, and using the information from the header t set the receiving apparatus into a suitable mode.

9. A method according to claim 8 in which the identifying header utilises a DTMF protocol.

10. A method according to claim 8 or claim 9 in which the modes include:

(a) a mode for recording a voice message,

(b) a mode for accepting and/or recording a fax message

(c) a mode for accepting and/or recording a modulated coded (i.e. "modem") message.

11. A method of transmitting messages according to any of claims 8 to 10 further comprising the step of storin the message in a buffer store before transmission to enable delayed forwarding and/or forwarding to multiple destinations.