GB2233858A

GB2233858A - Preventing facsimile redialling if non-standard service is not executable

Info

Publication number: GB2233858A
Application number: GB8929215A
Authority: GB
Inventors: Nam-Sup Lim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1989-06-30
Filing date: 1989-12-27
Publication date: 1991-01-16
Anticipated expiration: 2009-12-27
Also published as: GB8929215D0; GB2233858B; KR910002218A

Abstract

A calling station sends a command NSS which includes a request for a specific non-standard capability; the called station responds with a command NSF which includes data to indicate whether or not the requested capability is serviceable; and if not the calling station acts to inhibit its automatic re-dialling function so that it does not continue to occupy a communication line unnecessarily. <IMAGE>

Description

RE-DIAL CONTROL IN A FACSIMILE SYSTEM The present invention relates to a facsimile system and, in particular, to re-dial control therein.

Generally, in the case of terminal equipment such as a facsimile, which transmits and receives a message by means of a data transmission network, various control information is exchanged between the elements included in the data transmission network. Such control information is usually referred to as a protocol.

Relay-Request, Call Selection, Call Release, Message Transmitting and Receiving Flow Control may be good examples of the protocol.

Such rules of protocol are given in the CCITT (Comite Consultif International Telegraphique et Telephonique) recommendation T.30.

In order to transmit a message between facsimiles by means of public switch telephone networks (PSTN) now in use, the protocol applied in the CCITT recommendation T.30 must be satisfied. That is to say, if an exchange of the protocol is not made at an appropriate time, transmission of a message between facsimiles may not be achieved.

Non-standard capability in a facsimile system which exchanges a protocol with its counterpart station as aforesaid refers to various capability services including Relay-Request, a Mail Box and a Transmission-Receiving (Tx-Rx) Journal Report. Such non-standard capability services are usually controlled by a center (called) facsimile. When such non-standard capability services are requested by an originator (calling) facsimile, the above services are provided by the center facsimile. Such nonstandard capability services between the originator facsimile and center facsimile are also performed by exchanging the protocol commands, and the request for non-standard capability services is based upon the signaling format given in the CCITT recommendation T. 30.

Referring to the conventional non-standard capability services between facsimiles, when the center facsimile which can provide various non-standard capability services is dialed by the originator facsimile, an on-line connection is formed between these facsimiles. When a request for a specific non-standard capability service is made by the originator facsimile to the center facsimile, the center facsimile checks if such a specific non-standard capability service as requested can be provided. In the case that this is possible, the center facsimile provides the non-standard capability service to the originator facsimile.

However, prior art facsimile systems can have some problems with re-dialing when non-standard capability services are performed. That is, when a request for a specific non-standard capability service is made by the originator facsimile to the center facsimile, an error may occur because the called facsimile may be in a condition where it does not transmit to the calling facsimile the inexecutability of such a specific non-standard capability service as requested when it is not in a condition to provide the non-standard capability service.

On the other hand, the originator facsimile which made a request for a specific non-standard capability service has always performed re-dialing to the extent of a previously set number, as the originator facsimile is not provided with the requested specific non-standard capability service. Such redial is performed in the same way even if an error is committed when a non-standard capability service is requested.

Therefore, the originator facsimile performs the re-dial continuously, despite the fact that the originator facsimile is not provided with the specific non-standard capability service.

Consequently, the originator facsimile may occupy a communication line only to incur an unnecessary telephone charge.

Preferred embodiments of the present invention aim to control re-dialing of a calling facsimile by checking a requested non-standard capability service condition and by transmitting information of whether or not the requested service is executable to the calling facsimile.

Another aim is to control re-dialing by transmitting a desired specific non-standard capability service command to a called facsimile and by analyzing information which is transmitted from the called facsimile in response to the command of the calling facsimile.

According to an aspect of the invention, a facsimile system comprises at least one calling station and one called station, arranged to communicate with each other wherein; the calling station includes means for sending to the called station a Non-Standard Setup (NSS) command which includes a request for a specific non-standard capability from the called station; the called station includes means for detecting the NSS command, means for checking whether said capability is serviceable by the called station, and means for transmitting to the calling station a Non Standard Facilities (NSF) command which includes data to indicate whether said capability is serviceable; and the calling station further includes means for detecting the NSF command and inhibiting re-dial if the NSF command indicates that said capability is not serviceable.

Preferably the calling station further comprises means for setting normal transmission and reception when no NSF command is detected.

According to another aspect of the invention, there is included a method of controlling re-dial in the event of an error upon non-standard capability performance, occurring between calling facsimile and called facsimile. Preferably the method comprises: a Non-Standard Facilities (NSF) command transmission step for setting a non-standard capability to a NSF information field in response to a call from the calling station and transmitting the information field; a service deciding step for analyzing a Non Standard Setup (NSS) command which is transmitted from the calling station and detecting a specific non-standard capability request information loaded on an NSS information field and then checking if said non-standard capability request information is serviceable;; a performance function information transmission step for transmitting the requested non-standard capability performing information to the calling facsimile by setting said information to the NSF information field according to a decision made in the said service deciding process; an NSF command detection step for detecting if the NSF command exists in protocols transmitted from the called station; a first flag setting step for setting a first flag for normal transmission and reception when there is no NSF command in said NSF command detection process; and a re-try deciding step for analyzing the function performing information of the NSF information field which is transmitted from the called side and selectively sets a first flag in said process and a redial prevention flag for re-try prevention according to the content analyzed.

The invention may include a facsimile machine arranged to operate selectively as a calling station or a called station in a system or method according to any of the first and second aspects of the invention.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 is a hardware block diagram of one example of a facsimile system for carrying out an embodiment of the invention; Figure 2 is a diagram illustrating one example of communication made between facsimile systems such as illustrated in Figure 1; Figure 3 is a flowchart of re-dial performance; Figure 4 is a view showing phases B, C, and D of a facsimile which transmits and receives a protocol; Figure 5 is a flowchart showing nonstandard capability performance of a calling station; and Figure 6 is a flowchart showing nonstandard capability performance of a called station.

Referring to Figure 1, a central processing unit (CPU) 12 controls and processes the entire system according to a given program. Memory 14 storing program data, protocol data and character data accesses or stores the data under the control of the CPU 12.

Operating panel (OPE) 16 has a number of keys by which the system is caused to produce key data and inputs the key data to the CPU 12 when the key data is produced, and a display unit which can display data output by the CPU 12. Scanner 18 scans the image of a document and sends it to the CPU 12 in the form of digital image data.

Modem 20, controlled by the CPU 12, modulates the output data of the CPU 12 into analog data and outputs the input received from a calling facsimile by demodulating it. Network control unit (NCU) 22, controlled by the CPU 12, forms a communication loop on a telephone line and interfaces the signals of the modem 20 and the signals of the telephone line. In addition, a printer 24 prints out the content of a document under the control of the CPU 12.

Referring to Figure 2, there is illustrated a protocol command flowchart given in the CCITT recommendation T.30, for communication between facsimiles. It gives an illustration showing that a message is transmitted from a calling facsimile to a called facsimile, as an example of automatic transmission and reception.

Referring to Figure 3, there is illustrated a flowchart of re-dial performance, in which an image message is transmitted and received and a premess age protocol is communicated while a protocol is given to and received from a calling facsimile.

Referring to Figure 4, there is illustrated a view showing the operational state of a facsimile which transmits and receives a protocol. When a specific request for service (job) occurs in step 38, a protocol is transmitted and received and document content is transmitted and received in step 40. If an error occurs while the process of the step 40 is performed, the system returns to the step 38 after checking and setting for re-dialing in step 42, and repeats the same performance in the step 38 if a new job occurs.

The flowchart of Figure 5 shows the nonstandard capability service of an originator station (caller). The performance flowchart is a part of a protocol transmission and reception routine which is performed after on-line connection is achieved between calling station and called station. It comprises the steps of: detecting if an NSF (non-standard facilities) command is transmitted amongst the protocols transmitted from the called side; setting a first flag for normal transmission and reception when there is no NSF command detected in the NSF command detection process; and analyzing the function performing information of the NSF information field which is transmitted from the called station and selectively setting the first flag in the above process and a re-dial prevention flag for re-try prevention according to the content analyzed.

The flowchart of Figure 6 shows the nonstandard capability performance of a called station.

The performance flowchart is a part of the protocol transmission and reception routine which is performed in the same manner as in Figure 5 after on-line connection is achieved between calling station and called station. It comprises the steps of: setting a non-standard capability in the NSF information field in response to a call from the calling station and transmitting the NSF command to the on-lined calling station; analyzing an NSS (non-standard set-up) command which is transmitted from the calling station and detecting a specific non-standard capability request information loaded on the NSS command and then retrieving if it is serviceable; and transmitting the requested non-standard capability performing information to the calling facsimile by setting it in the NSF information field according to the decision made in the retrieving step.

Hereinafter, an operational example of the illustrated embodiments will be described with reference to the accompanying drawings, on the assumption that a system as shown in Figure 1 is connected to a calling facsimile through the PSTN (public switch telephone network) and a non-standard capability service of the Relay Request is requested by the calling facsimile.

When a CNG (Calling Tone) is sent out from the calling facsimile as illustrated in Figure 2, it is input to the CPU 12 through the NCU 22 and the Modem 20. The CPU 12 receiving the CNG sends a CED (Called Station Identification) to the calling facsimile through Modem 20 and NCU 22 and begins to exchange a protocol which corresponds to a pre-message with the calling facsimile in step 30 of Figure 3.

What is referred to as a pre-message in the above means a protocol command which is exchanged with the calling facsimile before image data is transmitted and received. It is also applied in the CCITT recommendation T. 30.

Accordingly, in the system of the called facsimile as illustrated in Figure 1, such protocols as NSF (Non-Standard Facilities), CSI(Called Subscriber Identification) and DIS(Digital Identification Signal) are sent out in the same order as shown in Figure 2 in the step 30 of Figure 3.

At about this time, the NSF, CSI and DIS commands are transmitted in the shape of HDLC (High Level data link control) frame. The called facsimile sets an information that it retains a non-standard capability in the NSF command before NSF command is transmitted and transmits an NSF command to the calling facsimile in this process, in step 60 of Figure 6.

On the other hand, the CPU 12 of the calling facsimile which received the CED command as illustrated in Figure 2 checks if the NSF command of the called facsimile is received through the NCU 22 in step 50 of Figure 5. In the case where there is no NSF command as a result of checking, the CPU of the calling facsimile sets a normal transmission and reception flag in step 56 and returns.

In the event that the NSF command is transmitted from the called facsimile as a result of checking in step 44, the CPU 12 of the calling facsimile sets a specific non-standard capability which will receive service to the NSS (Non-Standard Set-up) command in step 46 and transmits it to the called facsimile as illustrated in Figure 2. In other words, the CPU of the calling facsimile sets a relay request information to the NSS information field and transmits it.

On the other hand, the CPU 12 of the called facsimile which transmitted an NSF command in the step 60 of Figure 6 checks if an NSS command is transmitted from the calling facsimile in step 62. In the case where the NSS command is received, the CPU 12 of the called facsimile analyzes the received information of the NSS information field and checks in step 64 if a corresponding non-standard capability is performable.

At this time, judgment of whether a corresponding non-standard capability is performable or not can be easily checked by consecutively comparing requested specific non-standard capability information with non-standard capability information stored in the non-standard capability performing table set up in the range of inner memory on the part of the called facsimile's CPU 12.

If a requested specific non-standard capability performance service is possible as a result of checking in the step 64, the CPU 12 of the called facsimile sets an information that the requested specific non-standard capability (Example : Relay Request) is serviceable in the NSF information field in step 68 and transmits it to the calling facsimile through modem 20 and NCU 22.

If it is judged that a requested specific non-standard capability performance is not serviceable as a result of checking in the step 64, the CPU 12 of the called facsimile sets an information that the requested specific non-standard capability is not serviceable in the NSF information field and transmits it to the calling facsimile in step 66 of Figure 6.

Meanwhile, the CPU of the calling facsimile which transmitted a specific non-standard capability request information by setting it in the NSS command, namely, in the NSS information field in the step 46 of Figure 5 checks if an NSF command is received in step 48 of Figure 5. In other words, the CPU of the calling facsimile checks if there is a response to the specific non-standard capability information requested by itself from the called facsimile.

If an NSF command is not received as a result of checking in the said step 48, a normal transmission and reception flag is set in the step 56 as described before.

If, however, an NSF command (NSF information field) is received by being transmitted from the called facsimile as a result of retrieval in the step 48, the CPU of the calling facsimile analyzes the information content of the NSF information field received and checks if there is an information that the requested specific non--standard capability is performable, in the step 50.

If there is information that the requested specific non-standard capability is performable as a result of checking in the step 50, the CPU of the calling facsimile sets in the step 57 a non-standard capability transmission and reception flag set up in the inner memory and returns. In case there is no information that the requested specific non-standard capability service is performable as a result of checking in the step 50, the CPU of the calling facsimile checks in the step 52 if there is an information that the requested specific non-standard capability is not performable in the NSF information field.

When there is no information that the requested specific non-standard capability is not performable as a result of checking in the step 52, the CPU of the calling facsimile repeats from the step 46. In case there is an information that the requested specific non-standard capability is not performable as a result of checking in the step 52, the CPU of the calling facsimile sets in step 54 an error flag set up in the inner memory.

Then, the CPU of the calling facsimile communicates termination of pre-message transmission and reception in the step 30 of Figure 3 and calls off the Job performance when it recognizes that an error flag is set in the step 54.

The above condition is a condition for changing from document content transmission and reception (step 40) in Figure 4 to re-dial checking and setting (step 42). At this time, the CPU of the calling facsimile checks an error flag in the memory in the re-dial checking and setting condition and does not re-try by re-dialing if it is set.

As described above, the system may reduce unnecessary occupation of a transmission line and a resultant telephone charge by transmitting whether the center facsimile is able to perform a requested specific non-standard capability or not to the originator facsimile and thereby preventing re-dialing, when a request for performance of such a specific non-standard capability is made to the center facsimile by the originator facsimile.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A facsimile system comprising at least one calling station and one called station arranged to communicate with each other, wherein; the calling station includes means for sending to the called station a Non-Standard Setup (NSS) command which includes a request for a specific non-standard capability from the called station; the called station includes means for detecting the NSS command, means for checking whether said capability is serviceable by the called station, and means for transmitting to the calling station a Non Standard Facilities (NSF) command which includes data to indicate whether said capability is serviceable; and the calling station further includes means for detecting the NSF command and inhibiting re-dial if the NSF command indicates that said capability is not serviceable.

2. A facsimile system according to Claim 1, wherein the calling station further comprises means for setting normal transmission and reception when no NSF command is detected.

3. A facsimile system substantially as hereinbefore described with reference to the accompanying drawings.

4. A method of controlling re-dial in the event of an error upon non-standard capability performance, occurring between calling facsimile and called facsimile, the method comprising: a Non-Standard Facilities (NSF) command transmission step for setting a non-standard capability to a NSP information field in response to a call from the calling station and transmitting the information field; a service deciding step for analyzing a Non Standard Setup (NSS) command which is transmitted from the calling station and detecting a specific non-standard capability request information loaded on an NSS information field and then checking if said non-standard capability request information is serviceable;; a performance function information transmission step for transmitting the requested non-standard capability performing information to the calling facsimile by setting said information to the NSF information field according to a decision made in said service deciding step; an NSF command detection step for detecting if the NSF command exists in protocols transmitted from the called station; a first flag setting step for setting a first flag for normal transmission and reception when there is no NSF command in said NSF command detection step; and a re-dial deciding step for analyzing the function performing information of the NSF information field which is transmitted from the called station and selectively setting a first flag in said process and a re-dial prevention flag for re-dial prevention according to the content analyzed.

5. A method of controlling operation of a facsimile system, the method being substantially as hereinbefore described with reference to the accompanying drawings.

6. A facsimile machine arranged to operate selectively as a calling station or a called station in a system or method according to any of the preceding claims.