Automatic Remote Facsimile Testing System

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

This invention relates to the testing of facsimile transceivers and their telephone lines remotely by their users or by service technicians. It automatically accepts test fax transmissions from any fax transceiver, measures the transmissions and supplies measurements and advice to help users detect and correct problems. The invention can also be used for user training, preventive maintenance and confirmation of the success of initial transceiver installation and subsequent programming and repairs.

In 1991, there were approximately fifteen million fax transceivers in use worldwide. Most machines are used in businesses for important and often time-critical business correspondence, making continuous availability and reliability very important to users. The result of having a facsimile communications system out of service may be the loss of crucial business communications. Most fax transceivers in current use conform to standards developed by the Consultative Committee for International Telegraphy and Telephone (CCITT) known as the Group III standards that allow fax transceivers from any manufacturer to communicate with any other conforming machine. Fax transceivers communicate with one another over the worldwide public switched telephone network. Their transmissions are identical to ordinary voice telephone calls from the perspective of the telephone network. The term "facsimile communications system" is used herein to refer to the combination of a fax transceiver and the telephone equipment and local telephone lines that connect it to a long distance telephone network.

Troubleshooting of fax problems is complicated by the presence of many elements in the communications path and the inherent complexity of facsimile transceivers themselves. As a result, users usually leave problem diagnosis to specially trained technicians who work for fax manufacturers, retail outlets, fax service centers and telephone repair services. A successful fax transmission depends on private telephone equipment and public telephone networks, two fax transceivers, a suitable document for transmission and fax paper in the receiving machine. Users typically discover problems when they try unsuccessfully to transmit a fax message or when they hear from a remote user that their transceiver has transmitted an incomplete or illegible message or is unavailable to receive a message the remote user has tried to send.

When users experience a problem with fax transmissions, they usually lack the information and expertise to determine its cause. They often do not even know which equipment or service vendor is appropriate to contact for assistance. Most possible causes originate with products or services from several independent vendors each of which has unique arrangements for supporting and servicing their customers. As a result, users often call the most visible vendor, such as the vendor who sold them the fax transceiver. After incurring expense and delays, the vendor frequently informs the user that a product from a different vendor or user error is the source of the problem. When two vendors each assert that the other's product is the cause of a problem, users lack detailed knowledge to convince the appropriate vendor to assume responsibility. While this process may eventually result in a solution, it does so with unnecessary expense, delay and frustration because of the above previously unrecognized problems and limitations.

Test equipment designed for use by fax and telephone service technicians is available to locate fax transceiver and telephone carder problems. However, such equipment has the following disadvantages:

1. It requires a trained technician to operate and is unsuitable for laymen. The user must expend effort locating and contacting a technician and waiting for results, results that vary with the expertise of the technician.

2. It requires prior contact between the technician and the user to arrange for a test transmission.

3. The technician must monitor the test transmission and read and interpret the results for the user.

4. Results and advice are given to users verbally and are not available as written form.

Certain fax transceiver models have a feature known as "remote diagnostics." This feature permits a trained technician with special equipment at a remote location to connect with the transceiver by telephone, examine diagnostic and configuration information stored in the transceiver and make changes to certain settings. The remote diagnostics feature has the following disadvantages:

1. It uses proprietary communications protocols that are unique to each vendor or model and do not conform to any international standard. As a result different test equipment and technician training are needed for each vendor's fax transceivers and sometimes for each model.

2. It requires a trained technician to operate and is unsuitable for laymen.

3. It requires contact between the user and the technician to report the problem, evaluate the need for a remote diagnostics session and report the results of the session to the user, often requiring several telephone calls.

4. The technician must conduct the session manually and interpret the results of any information discovered for the user.

5. Test results and advice are commonly given verbally and are not available in written form.

Most fax transceivers have a local copy or self-test function that permits the user to make a copy of a document using the machine's scanner and printer. This function allows users to examine some aspects of their fax image quality. Local copies, however, are not representative of the quality of fax transmissions actually received on remote machines, however, because transmitted images may have been degraded by the local machine's fax modem or by telephone carriers, components that are not tested by the self-test function. This deficiency limits the function's diagnostic uses.

The above disadvantages and problems with existing fax test equipment, remote diagnostic features and self-test functions have existed for ten years or more and have not been previously recognized in the prior art.

Users of facsimile communications systems may test their transceivers by transmitting a test fax page over the public switched telephone network to a system that makes measurements of the test transmission and of telephone line characteristics. Measurements are analyzed to locate possible anomalies. Results of analysis, the measurements themselves and a copy of the user's test fax are incorporated into a test report. The test report is delivered to users as a fax message or spoken announcement during the same call or a second call. By providing a system that sends and receive fax messages like an ordinary fax transceiver but also can make and process measurements while it is doing so, it is possible to provide diagnostic information and advice quickly and automatically to users while they use their fax transceivers in ways to which they are already accustomed. By relying solely on standard communication exchanges of which all standard fax transceivers are capable, the system can universally provide useful diagnostic information and advice, no matter what the make and model of the transceiver.

In one mode of operation, the user initiates a test by automatically transmitting a sample document, such as a cover page or test chart to a special fax telephone number where the test system is located. During the transmission the system makes measurements of the incoming test transmission and the telephone line and learns the area code and telephone number of the calling fax transceiver. The system analyzes the measurements and prepares a test report, which is then immediately delivered to the caller by fax message or voice announcement. If the report is delivered by fax, it is sent to the area code and telephone number received during the test fax transmission. If callers request the test report by voice, they are asked to identify the tested fax transceiver by area code and telephone number and are then given test results related to the designated machine. The system maintains a call record for each call received in an activity log file, containing the measurements made and a copy of the received test fax image. The activity log may be accessed by modem by a remote computer system.

In another mode of operation, the user places a manual call to the fax testing system using a telephone handset associated with the fax transceiver. The system responds with a tone or a voice prompt introducing the system and the explaining the available options. Using Touch Tones.SM. generated by the fax transceiver's keypad, the user then selects from available options that include selecting the type of measurements desired, selecting how the test report should be delivered, identifying the telephone number where the test report should be sent and optionally identifying a method of payment for the test results. ("Touch-Tone" is a registered servicemark of AT&T.) After responding to the prompts and during the same call, the user transmits the test document. The user also can request information about the system and stop repeated attempts by the system to deliver a fax message to facsimile communications system that is out of order. Functions which do not involve transmitting a fax message may be accessed from a standard telephone set rather than a facsimile transceiver.

FIG. 1 is a block diagram of the invention.

FIG. 2 is a simplified flow chart of the process of receiving test fax transmissions and delivering test reports.

FIG. 3 shows the layout of the test report.

FIG. 4 is a detailed flow chart of processing accomplished by the invention, including receiving test fax transmissions, transmitting test reports and other interactions with users and the system operator.

FIG. 1 shows a block diagram of the facsimile testing system. To carry a significant number of simultaneous telephone connections, modem switched telephone networks digitally encode and intermix (multiplex) signals for several calls on trunk circuits. A T1 circuit, for example, carries 24 simultaneous telephone connections. In the present system, a T1 circuit A1 interfaces the system to the public switched telephone network. Typically the T1 circuit A1 will be connected directly to a long distance (interexchange) carrier such as AT&T, through which fax users can access the system nationwide on 800, 900, and normal telephone numbers. The T1 circuit A1 is also connected to a telephone switch or channel bank A2, which separates 24 individual telephone connections from the digital signal present on the T1 circuit A1. Certain of the 24 circuits receive inbound calls from users of the system; others are outbound circuits to be used to send test reports to users. Each inbound circuit is connected to both a fax modem circuit board with test capabilities and associated low level software A3, A5, and a voice processor circuit board with associated low level software A4, A6.

The GammaFax.TM. CP circuit board from GammaLink Graphic Communications, Inc., of Sunnyvale, Calif. may be used for the fax modem circuit boards with test capabilities, A3, A5 and the fax modem A9, A10. "GammaFax" is a trademark of GammaLink Graphic Communications, Inc. The DIALOG/41B.TM. from Dialogic Corporation of Parsippany, N.J., may be used for voice processor circuit board A4, A6. "DIALOG/41" is a trademark of Dialogic Corporation.

Circuit boards A3, A4, A5, A6, A8 and A9 are connected to the bus of a personal computer A7. Fax modems A9 and A 10 are connected to outbound telephone circuits provided by the switch or channel bank A2. Also connected to the computer A7 bus are a hard disk A8 and a modem A11. Modem A11 is connected to the public switched telephone network through a standard two wire circuit A12. A system operator can reach the modem A11 by calling a special maintenance telephone number separate from the telephone numbers available to users.

The simple embodiment described above can handle two simultaneous incoming test fax transmissions and two simultaneous outgoing test reports. The design of the invention is modular however, and can handle many simultaneous incoming calls by adding fax modem/tester circuit boards like A3, voice processor circuit boards like A4 and fax modem boards like A9.

Similarly, the system can be reduced to handling a single call at a time by using only one of each type of circuit board. In this case the T1 digital trunk line A1 and switch or channel bank A2 may be replaced by a standard two wire telephone circuit for both incoming and outgoing calls.

FIG. 2 shows a simplified flow chart of the basic mode of operation of the system for automatically testing faxes. In step B1, the system waits for incoming test calls from users. Users may reach the system by calling a variety of telephone numbers, such as 800 numbers when sponsors pay for the costs of operating the system and 900 numbers when users pay.

At the beginning of the call in step B2, the service receives information from the telephone network identifying the call. This information includes Automatic Number Identification (ANI), which contains the telephone number of the caller. It also includes Dialed Number Identification Service (DNIS) which contains telephone number such as an 800 or 900 telephone number the user called to reach the system.

When the telephone connection is completed, the system responds as if it were a standard fax transceiver and receives the test fax transmission from the user. During the reception of the test fax transmission, the system performs and stores several measurements of the telephone line and the fax communication that is underway. It also saves data representing the test fax page sent by the user. At the beginning of the call, any standard fax transceiver conforming to the CCITT Group III standards will send its Transmitting Subscriber Identification (TSI) which contains the area code and telephone number where the fax transceiver is located. The system captures the TSI for later use. At the conclusion of the test fax transmission, the system disconnects from the telephone line, as if it were a standard fax transceiver that had just completed receiving a normal fax message.

In step B3, the system then processes the measurements and other information collected during the call and builds a file containing a custom test report. It reviews the measurements to see if any is outside of acceptable bounds and inserts one or more paragraphs into the test report for each unacceptable measurement. It also includes the measurements themselves in a table in the report. Finally a copy of the original test fax page sent by the user is appended to the report.

In step B4, the completed test report is then delivered to the user by facsimile or voice. The system must determine what fax telephone number should receive the test report. In practice, the TSI containing the user's fax telephone number is often missing or incorrect. This is so because the TSI must be programmed by the user into the fax transceiver and the fax transceiver may be successfully used even when the TSI is missing or incorrect.

The ANI received from the telephone network also represents the user's fax telephone number. Occasionally ANI is missing or it represents a central telephone number rather than an extension telephone number. The system sends the test report by fax to the ANI telephone number if it is present and appears to be accurate and to the TSI telephone number otherwise. If the designated facsimile transceiver is busy when the system calls, it tries the call again approximately every ten minutes up to 24 times.

The system maintains a log file that records all calls to the system. After the test report has been delivered, in step B5, the system adds a record to the log file containing the date and time of the call, the measurements made, a copy of the test fax page, and information relating to the delivery of the test report to the user. The system then waits for another call.

Because the system contains multiple incoming telephone lines and equipment to handle them, it is capable of handling multiple simultaneous calls. Even though a call may be at a certain stage in the process described above, the system is still ready for additional incoming calls.

To understand how the processing of the basic testing mode is performed by the main components of the system, refer again to FIG. 1. All incoming calls are received on a T1 digital trunk line A1. The switch or channel bank A2 decodes the digital signals from the digital trunk line A1 and distributes each new call to an available pair of circuit boards, such as fax modem/tester circuit board A3 and voice processor circuit board A4. For a call allocated to this pair of circuit boards, the voice processor circuit board A4 detects the ringing of the telephone line and goes "off hook" to answer the call. At the beginning of the call the telephone network sends ANI and DNIS signals and these signals are received and stored by voice processor circuit board A4. Once the telephone connection is fully established, the user's fax machine sends a calling tone (CNG) to initiate a facsimile transmission. The voice processor circuit board A4 detects this signal and passes appropriate data to the computer A7.

The computer A7 instructs the fax modem/tester circuit board A3 to take over the call in progress. The fax modem/tester circuit board A3 then receives and measures the test fax transmission from the user. At the conclusion of the call, both circuit boards disconnect from the call. The fax modem/test circuit board A3 then passes a call record to the computer A7 containing details of the completed call. The computer A7 then stores the record in a received queue file on hard disk A8.

When the computer A7 becomes available for further processing it retrieves the call record from hard disk A8 and prepares a test report. The completed test report is stored in a file and a record describing the destination for and filename of the test report file is stored in a queue file on hard disk AS.

When a fax modem such as fax modem A9 becomes available, the test report is retrieved from hard disk A8 and sent to the user.

FIG. 3 shows the layout of a sample test report. The report content will vary widely depending on the measurements. A simple case associated with the embodiment listed in the Appendix is shown in the sample. The header C1 identifies the test report and its recipient. Sample text might consist of:

The body of the report C2 contains selected paragraphs resulting from the analysis of the measurements. Sample text might consist of:

Our facsimile diagnostic system recently received your test fax. Your transmission was analyzed automatically and the results are given below. See the FaxChek instructions for help in interpreting these results. The last page of this report is a copy of your original test fax that you can visually examine for defects. Thanks for using the FaxChek system.

Your answerback (`CSID,` `TSI`) is correctly set to your fax phone number.

Your line noise of -63 dBm was very quiet, which is good.

Your signal strength of -21 dBm was stronger than ideal. If your machine is serviced for other reasons, you should have it checked.

Our automatic analysis revealed no problems. Your fax machine and local phone service appear to be operating correctly. However, you may discover other problems by examining the image quality of this report as explained in the user's instructions.

The technical measurements leading to the above conclusion(s) are listed below. If you experience fax communications problems, these measurements may be of interest to your telephone company or fax machine serviceperson.

The report may be followed by a protocol trace report and is followed by a copy of the test fax transmission if it was received during the user's test fax transmission.

The basic testing mode allows users to simply and automatically send a test fax transmission and receive a basic test report. The interactive mode, by contrast, allows the users to interact with the system by touch tones to select among alternative services and make other choices. The user initiates an interactive call by picking up the telephone handset on the facsimile transceiver and manually calling the system without sending a test fax transmission. Referring again to FIG. 1, processing of incoming calls is identical up to the point where the ANI and DNIS signals are received and stored by voice processor circuit board A4. Because the user is placing a voice call, the facsimile transceiver does not send the CNG tone to indicate that a fax transmission is desired. The voice processor circuit board A4 waits for four seconds but does not detect the CNG tone. It then makes a voice announcement similar to the following:

"Welcome to the FaxChek facsimile testing service. This call will cost $2.75. If you hang up before the tone, you will not be charged. (Pause, tone.) For an introduction to the FaxChek service, press 1. To begin a test press 2. For results from a previous test, press 3. To cancel further attempts by the FaxChek system to send to your fax machine, press 4. If you are having trouble using the service, press 5."

If the user presses 1, a spoken announcement describes the system and gives brief instructions by voice.

For choice 2, the system asks the user to select a basic test or a test with protocol trace. The system then asks the caller to enter the fax telephone number where the test report should be sent. It then asks the user send to a test document and then proceeds as in an automatic basic testing mode call. However, if the user selected the test with protocol trace then a special trace file is kept of all interactions between the user's facsimile communications system and the system. The trace report is later appended to the test report. The test report will be sent to the fax telephone number entered by the user rather than the TSI or ANI telephone number.

For choice 3 the system asks the user for the fax telephone number of a facsimile transceiver that has been tested during the last 24 hours. If the system has any test reports for that fax telephone number it tells the user how many reports are available and asks the user whether the reports should be delivered by fax or voice. If the user selects fax delivery, the system asks the user for the fax telephone number where the reports should be sent, records the number and sends the reports. If the user selects voice delivery, the test results are spoken to the user.

For choice 4, the system asks the user for a fax telephone number of a facsimile transceiver to which the system should discontinue sending attempts. This function is required because repeated ringing or partial deliveries of a document to a machine that is out of order can become annoying to the user.

For choice 5, a spoken announcement gives troubleshooting advice.

For each completed call, the system adds a record to the log file containing the date and time of the call, the caller's telephone number as reported by the telephone network (ANI, the telephone number the user called to reach the service (DNIS), the information entered by the user by touch tone, the measurements made, a copy of the test fax page, and information relating to the delivery of the test report to the user.

In all other respects, operation of the interactive mode is identical to the basic testing mode.

FIG. 4 is a detailed flow chart for all processes in a preferred embodiment of the system, including the basic testing mode and the interactive mode. The flow chart shows the process of answering an incoming call. The description below refers to individual fax modem/tester circuit boards, voice processor circuit boards or fax modem circuit boards by way of example only. In actual operation one of several identical components may be handling a particular step depending on how many calls are in progress at the time.

Step D1 represents the start of a process that takes place when ringing is detected on any available inbound channel, where each channel consists of a voice processor circuit board like A4 and a fax modem/test circuit board like A3. Ringing is caused by a call initiated by a user of the system, who may be making an automatic or voice call.

In step D2, an available voice processor circuit board A4 responds to the ringing by answering the call. Using special services available in the connection with the long distance network, two pieces of information are received before the caller's side of the connection is established. This information consists of the telephone number of the caller's facsimile transceiver or voice telephone, ANI (Automatic Number Identification), and the number the caller dialed to reach the service, DNIS (Dialed Number Identification Service). The system is available through several telephone numbers and it needs to log which number was used.

In step D3, the callers side of the connection is established. If the current call is a Group III facsimile transceiver making an automatic transmission of a test fax transmission, then the transceiver will transmit a calling tone, CNG, at 3.5 second intervals. The voice processor circuit board A4 monitors the line for 3.5 seconds and determines whether CNG was transmitted or not. If not, the call is assumed to originate with a person seeking to interact with the system and control passes to step D19, described further below.

In step D4, which takes place if CNG was detected in step D3, the system prepares to receive a test fax transmission. Information collected by the voice processor circuit board A4, including date and time of call, ANI and DNIS are temporarily stored in a record in voice queue file on hard disk A8 for later use. Control is passed to the fax modem/tester A3.

In step D5, fax modern/test circuit board A3 exchanges preliminary information (handshaking signals) with the calling facsimile communications system. Information captured from the calling facsimile transceiver during this exchange includes:

TSI (Transmitting Subscriber Identification), the telephone number of the facsimile transceiver

DCS (Digital Command Signal), identifying a set of capabilities to be used for the transmission

NSS (Non-Standard Setup), identifying the manufacturer of the transceiver and any non-standard features to be used during the call

In step D6, the calling facsimile transceiver transmits a modem "training signal" of known content so that the system's fax modem can adapt to the signal's characteristics and determine if reception will be sufficiently error free to complete the transmission. The fax modem/test circuit board A3 measures signal strength and signal quality. During a silent period, fax modem/test circuit board A3 measures telephone line noise. The three measurements are saved for use in the test report.

In step D7, the calling facsimile transceiver transmits its test fax page and fax modem/test circuit board A3 receives the page image and stores it in a file on hard disk A8.

In step D8, the calling facsimile communications system and the fax modem/test circuit board A3 exchange messages to determine if the message transmission has completed successfully. An Error Status code identifying the success or type of failure of the transmission is determined.

Fax modem/test circuit board A3 disconnects from the telephone line and saves the error code and all other measurements taken as a record in a received fax queue file on hard disk A8.

In step D9, the oldest record in the received queue file is retrieved in preparation for building a test report. In the simplest case where only one call is handled at a time, this record is the one stored in the previous step D8. The voice queue file record corresponding to the same call is also retrieved. The voice record contains additional information about the call and the choices made by the user in steps described below.

In step D10, the process of building a test report file begins by storing a header identifying the date and time the test fax transmission was received, the telephone number of calling facsimile transceiver and the telephone number the user called to reach the service. A paragraph introducing the test report is added. The Signal to Noise Ratio measurement is calculated from the Signal Strength and Line Noise measurements. Measurements made during the test fax transmission are reviewed to determine if any measurement is outside of acceptable bounds. The following evaluations are performed:

Each of the evaluations made above can result in the addition of one or more paragraphs to the test report.

In step D11, the actual measurements are assembled in a table with informative descriptions. A legal notice is added. This step concludes the assembly of the main body of the report.

In step D12, if the user requested a protocol trace in step D22, the raw trace information is formatted into a trace report and added at the end of the report. In either case the test fax page image that was stored in step D7 is added to the test report.

In step D13, the completed report is stored in a file and a record is stored in a transmit queue file describing the desired fax test report transmission. If the user entered a valid destination fax telephone number in step D22, the test report will be sent to it. If the number entered by the user is not used and ANI was received and appears to be a valid telephone number, the test report will be sent to the ANI telephone number. If ANI is not used, the test report will be sent to the telephone number represented by TSI. The oldest record in the transmit queue file is read and transmission is attempted by an available fax modem circuit board such as A9. In the simplest case where only one call is handled at a time, this record is the one stored in the current step D13.

In step D14, if the test report was successfully transmitted or if during the attempt it appeared that a voice telephone number rather than a facsimile transceiver was called, control passes through D16 (designated with the letter A) to step D17. All steps marked with the letter A flow to step D17.

In step D15, if the test report was not successfully transmitted after 24 tries, control passes to step D17. Otherwise the number of attempts to deliver the report and the error status from the last attempt are updated in the table of measurements in the test report and a new transmit queue file record is established so that transmission will be tried again by step D 13.

In step D17, which is processed after any point marked with the letter A, the log file stored on hard disk A8 is updated with a call record containing the raw measurements and other information collected during the call, the number of attempts that were necessary to deliver the test report and the status of the last attempt to deliver the report.

In step D18, the processing resulting from a call to the system is concluded. At this point the system will attend to other necessary processing or begin the processing of a new call with step D1.

If in step D3, at the beginning of the call, no calling tone (CNG) was received, the caller is presumed to be a user desiring an interactive session rather than facsimile transceiver making and automatic transmission and control passes to step D19.

In step D19, voice processor circuit board A4 plays a stored voice message consisting of a preamble and a voice menu, for example:

"Welcome to the FaxChek facsimile testing service. This call will cost $2.75. If you hang up before the tone, you will not be charged. (Pause, tone.) For an introduction to the FaxChek service, press 1. To begin a test press 2. For results from a previous test, press 3. To cancel further attempts by the FaxChek system to send to your fax machine, press 4. If you are having trouble using the service, press 5."

In step D20 the voice processor circuit board A4 receives the caller's response to the voice menu, which should consist of a touch tone for a digit one through five. Control passes to one of five further steps depending which number key the user pressed on the facsimile transceiver's or telephone's keypad.

If the user presses 1, control passes to step 21 and a spoken announcement describes the system and gives brief instructions by voice.

If the user presses 2, control passes to step D22. The system asks the user to select a basic test or a test with protocol trace. If the user selects a protocol trace, a special trace log is kept of all interactions between the user's facsimile transceiver and the fax modem/tester circuit board A3. The system then asks the caller to enter the fax telephone number where the test report should be sent. The caller can, for example, request that the report be directed to a service technician's facsimile transceiver rather than the caller's or to a different facsimile transceiver at the user's office if the tested facsimile transceiver is incapable of receiving. The system then asks the user send to a test document. Control then passes to step D4.

If the user presses 3, control passes to step D23. The system asks the user for the fax telephone number of a facsimile transceiver that has been tested during the last 24 hours. It searches the portion of the log file representing the last 24 hours for call records corresponding to the designated fax telephone number and counts the number of such reports located. In step D24, the user is told how many reports have been located and asks whether they should be delivered by voice or by fax.

In step D25, the choice of voice or fax delivery is received. If the user chooses voice delivery, control passes to step D26, otherwise to step D9.

In step D26, test results corresponding to call records located in the log file during step D23 are announced to the user by voice processor circuit board A4 in a process corresponding to the generation of a written test report in step D9 through D12.

If the user presses 4, control passes to step D27. The system asks the user for a fax telephone number of a facsimile transceiver to which the system should discontinue transmitting attempts. This function is required because repeated ringing or partial deliveries of a document to a machine that is out of order resulting from repeated retries step D13 can become annoying to the user.

In step D29 the system locates any transmit queue file records and test reports corresponding to the designated fax telephone number that are waiting to be transmitted by step D13, deletes them so that they are not tried again and passes the information in them to step D17.

If the user presses 5, control passes to step D27. A spoken message gives troubleshooting advice.

At the conclusion of any call to the system that was placed to a 900 number, the telephone carrier saves special billing information and bills users through arrangements with local telephone carriers. The high degree of automation and low cost of 900 billing allows the service to be made available publicly at low cost. Any public user may thus make an automatic test fax transmission to the system with no prior arrangement, without having to identify his or her identity, name and address for billing purposes.

Modifications and additions can be made to the embodiment disclosed above without departing from the invention as defined in the claims below.

Facsimile transceivers conforming to Group II and Group IV CCITT standards and copiers with communications capability can be tested as well as Group III transceivers.

The voice processor circuit board, the fax modem/tester circuit board and fax modem circuit board could be combined into a single circuit board. Additional capability on the circuit board could substitute for computer A7. Delivery of test reports could be made through fax modem/tester circuit boards A3 and A5 instead of separate fax modems A9 and A10. Fax modem/tester A3 or A5 could be used instead of a separate modem A11. All the components shown in FIG. 1 can be integrated into a conventional facsimile transceiver, so that the resulting transceiver is capable of normal fax message traffic as well as diagnosis of other machines. A conventional facsimile transceiver with a port such as an RS-232C port could be combined with a computer to provide all necessary functions.

Instead of pairing voice processor circuit boards such as A4 with fax modem/tester circuit boards such as A3, the assignment of fax modem/tester circuit boards to individual voice processor circuit boards could be controlled by a crosspoint switch. Since calls for information only do not require a fax modem/tester circuit board, a smaller number of boards can be used to service only the calls requiring fax services.

The voice processor circuit boards can be eliminated. An incoming call is then answered in step D2 directly by a special fax modem/test circuit board with tone generation and touch tone decoding such as the GammaFax CP/DFX circuit board from GammaLink Graphic Communications, Inc. This method is used in the source code in the Appendix. ANI and DNIS are then received by the special circuit board. Instead of steps D19, D20 and D21, the circuit board prompts the user with a simple tone. The user then enters much tone sequences separated by the pound or star key to make choices that would have been made in steps D20, D22, D23, D24, and D28. Options that involve delivery of information by voice and their associated steps D21, D26 and D27 are unavailable.

Requested information including test reports could be delivered to callers by means of electronic mail, computer networks or by modem or touch tone signaling over the public switched telephone network.

Digital trunk line A1 can be a standard two-wire switched circuit, an ISDN link, a dedicated instead of a switched line or any other form of communications link. Switch or channel bank A2 can be eliminated when one or more individual telephone circuits are available.

Pulse dialing or voice command recognition could be used in place of detection of touch tones.

An optical disk or semiconductor memory could be used in place or hard disk A8.

The system can decode in step D10 the DCS signal received from the calling facsimile transceiver during step D5 and include information in the test report on transmission options chosen by the facsimile transceiver such as the data rate, minimum scan line time, 2400 bit per second handshaking capability, error correction mode and maximum recording width capability.

The system can make a second set of measurements of the facsimile transceiver that is being tested and its telephone line at the time the test report is starting to be sent back to the facsimile transceiver. The results of these additional measurements can be incorporated later in the body of the report before transmission to the user.

The system also can store the results of several incoming test fax transmissions and summarize the overall results in the test report. Since problems with both facsimile transceivers and telephone lines can be intermittent, such a test discovers more problems than a single test.

The system can deliver the test report to the calling facsimile transceiver during the original test fax transmission instead of during a separate call if the facsimile transceiver is capable of "turn-around polling." This feature allows fax messages to be transmitted in both directions during a single telephone connection.

Instead of sending an arbitrary page as a test fax transmission, the user can send a standard test chart of known content, such as CCITT Test Chart No. 3 as described in the CCITT Blue Book, Volume VII, Fascicle VII.3, Recommendation T21. Examination of its image resumed with the test report allows assessment of resolution and image quality. The image of the chart received during the transmission of the test fax page can also be analyzed during step D10 for various defects and the probable causes of such defects are identified in additional paragraphs in the test report. For example a vertical white band in the image with sharp definition at the edges is frequently caused by dirt or a scrap of paper blocking access to a portion of the document scanner in the calling facsimile transceiver. Several vertical white bands with blurred definition at the edges are often caused by poorly adjusted scanners. Small black specs (pixels) scattered randomly in horizontal bands the full width of the image are typically caused by intermittent line noise. A thin, perfectly straight vertical black line a multiple of one pixel wide is usually caused by a defective scanner or primer element. Stretched or compressed images can be caused by defective document handling mechanisms.

During the transmission of the modem training signal in step D6, the system can perform a spectral analysis of the signal using a fast fourier transform. The resulting spectrum can be compared with various profiles to identify probable problems with the transmit equalizer in the calling facsimile transceiver, reactance or metallic problems with telephone lines, improper loading coil placement on telephone lines and the presence of telephone line digital carrier systems that interfere with the facsimile signal.

By analyzing signals sent by the calling facsimile transceiver during steps D5 and D6, the system can measure steady state distortions such as phase modulation, phase jitter, amplitude modulation and amplitude jitter. Similarly, transient distortion in phase and amplitude, impulse noise, drop outs, retrainings and data rate changes can be measured. All measurements can be compared with acceptable bounds in step D10 and paragraphs added to the test report as appropriate.

The raw measurements can be formatted aM added to the table of measurements in the test report in step D11.

The testing process could begin with a test fax transmission originating with the system rather than a user of the facsimile transceiver. The system could automatically schedule monthly or quarterly tests. In this way regular preventive maintenance can be conducted automatically by the system on a regular schedule.

The system could automatically deliver a special test report to a special destination in addition to the one specified by the user, such as a manufacturer's service center.

The system can maintain a database of user accounts on hard disk A8 to manage prepaid usage accounts limited by time and number of calls. During step D2, the received ANI, representing the telephone number of the calling facsimile transceiver is searched in the user account database on hard disk A8. Each ANI in the database has an account record containing a personal information number (PIN), the number of calls made by the account, a maximum number of calls allowed for the account and an account expiration date. When the account record is located, if the number of calls previously made is less than the maximum and the account is not expired, the number of calls made is incremented and the call proceeds to step D3. Otherwise the caller is informed that the account is expired. The user is informed of ways to establish a new account and of alternate billing arrangements and the call is terminated. If an account record for a user is not located, the user is offered the option of establishing an account by entering a PIN, supplied by a sponsor of the system. When a valid PIN is correctly entered, an account record is then established with a maximum number of calls and an expiration date in accordance with the sponsor's policies. A valid account may be assigned to a different facsimile transceiver by calling from the new facsimile transceiver so as to send a new ANI and responding to voice prompts. PINs defined for user accounts that last the duration of a new facsimile transceiver warranty period can be sponsored by the transceiver's manufacturer or by a reseller of the facsimile transceiver.

The system can be enhanced with a credit card billing option. In step D22, the user can be asked for a credit card number that the system should bill for the cost of the test. In a new step preceding step D4, the system would connect by modem with an automated credit card system, transmit the card number and amount and receive an authorization number to be stored with the call record in step D17.

The system can be made available simultaneously through different telephone numbers, each of which is routed through a different long distance carder. If a test report indicates a telephone line problem, the user can determine if the problem is caused by the long distance carrier by conducting further tests using alternate carriers and comparing the resulting test reports.

In step D22, the system could ask the user to identify the make and model of the facsimile transceiver that is being tested. Using information on the capabilities of various models stored on hard disk A8, the system could test additional model-specific features. For models containing a remote diagnostics feature, the system could collect diagnostic and activity log information stored in the facsimile transceiver and perform additional analysis and reporting. The system could also refer the user when appropriate to a technical support telephone number sponsored by the manufacturer of the facsimile transceiver.

During step D22, the system can ask the user to identify various symptoms that cannot be detected through the automatic interaction between the user's facsimile transceiver and the system. This information can be analyzed along with the measurements to generate more specific advice. For example, while the system can measure images sent by the user, it has no way to measure the visual quality of test reports or other documents received by the user. The system can ask, for example, "Do all your received faxes have straight black vertical lines in the same position on the page?" If measurements indicated no scanner problem, the system would add a paragraph to the test report identifying the facsimile transceivers printer as the most likely cause.

The system can track its own system errors as well as the log file and test fax transmissions and generate a variety of reports based on the accumulated information. Reports could include, for example, reliability statistics on various facsimile transceiver models. The accumulated information can be periodically downloaded to a system operator through modem A11 or fax modem A9 or A10. The accumulated information could be periodically purged.

The system can be provided with a system operator's interface activated through modem A11 or one of the fax modems. The system operator can connect to the system using a remote computer and have the option of monitoring the call handling activities of fax and voice circuit boards assigned to telephone lines, examining the flow of measurements and test reports, re-initializing the software, enabling the printing and logging of test fax transmissions, performing hardware tests on components of the system, and exchanging files such as reports, the log file, the error file or the user account database with a remote computer.

It is intended that the claims below be interpreted as including the above modifications and additions as well as others suggested by the reading of the above descriptions and drawings.

The system relies only on information available in interchanges defined by international standards. It is thus compatible with all facsimile transceivers conforming to the standards. Because the system requires only standard sending and receiving actions by the user and the test results are analyzed and explained in layman's language, the system is uniquely capable of being used by ordinary fax users as well as technicians. The process of conducting a test is not a special procedure but involves the exercise of normal transmission and reception functions. Events observed during this exercise by the user can provide additional troubleshooting clues.

The system is fully automated and can be constructed from inexpensive components, so that it can be offered at little or no cost to all callers. In this regard the system is superior to expensive, specially built test equipment that can be operated only by trained technicians. Because it is constantly available with no technician required, it speeds up the preliminary stage of problem diagnosis at an early stage of troubleshooting when the user does not even know which vendor's technician to contact.

Returning a copy of the user's test fax transmission as part of the test report allows the user to compare it with the original test page, examining its image quality after passing twice through the telephone network. Specific types of degradation of the image can often be detected by visual examination that are not detected by the system's analysis. The user is given the reassurance of seeing image quality first hand; this is not usually possible because normal fax transmissions are always sent to a remote location.

Extensive test results from large numbers of test fax transmissions are accumulated in the log file. Facsimile transceiver manufacturers can analyze the file to evaluate performance of their facsimile transceiver models in the field, make comparisons with competitive products, determine the need for possible product field upgrades or recalls and design new transceiver models.

The system is capable of making telephone line measurements specifically of the caller's local telephone loop even though most fax transmissions involve two local loops and a long distance carrier. The system is usually connected to the public switched telephone network by means of a digital trunk line directly to a long distance network. This type of connection eliminates the second local loop that is present in a typical fax connection, and with it a source of noise and other line impairments that could interfere with remote local loop measurements. The selected long distance carrier itself will be a high reliability all-digital network that would rarely interfere with measurements.

Fax problems frequently are detected when two facsimile transceivers appear incapable of communicating with one another. Often there is no clue indicating which of the two is the cause of the problem. Users of each transceiver can perform a test using the system. The location of the system in the middle of a long distance network isolates the two local telephone loops, allows separate but equivalent tests of the two facsimile transceivers and their local loops. Comparison of the two test reports will often indicate the source of the problem.

Facsimile technicians frequently have to make field adjustments to installed facsimile transceivers, particular of modem signal strength. Previous to the present invention, technicians have had to have a second technician available at a second remote location to make signal strength measurements using manual equipment. The invention allows such adjustments to be made by the single field technician at considerable savings.

Facsimile transceivers contain many moving parts that wear out, some of them delicate. They process documents that may contaminate the document path and scanner and use fax paper that gradually abrades the print head and other components in the paper path. Telephone lines, particularly in the local loop, can slowly degrade as wiring and connections age. As a result, facsimile transceivers and their telephone lines require preventive maintenance for reliable operation. Using the present system, users may run periodic tests for purposes of preventive maintenance. Resulting test reports can reveal emerging problems such as increases in telephone line noise or dirt on document scanners. Users can then take corrective action before their vital fax communications capability is disrupted. The cost of regular technician visits can be reduced and the reliability of fax communications enhanced.

The following Appendix contains the source code for a simple embodiment of the system for use with GammaFax CP/DFX fax circuit boards. It does not use voice processor circuit boards but relies instead on a tone prompt and touch tone input for user selection as described above. ##SPC1##