GB1602675A

GB1602675A - Character transmission

Info

Publication number: GB1602675A
Application number: GB19493/78A
Authority: GB
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1977-10-27
Filing date: 1978-05-15
Publication date: 1981-11-11
Also published as: JPS5471920A; DE2748240B2; IT1100143B; FR2407618A1; SE7811140L; IT7829076A0; NL7810694A; DE2748240A1

Description

(54) CHARACTER TRANSMISSION (71) We, SIEMENS AKTIEN GESELLSCHAFT, a German Company, of Berlin and Munich, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to an arrangement for the transmission of characters from a transmitting terminal device to a receiving terminal device, wherein the transmitting terminal device emits code words which code the characters character by character and wherein the receiving terminal device produces graphic patterns described by data words.

It is already known to use teleprinters or data printers for the transmission of characters from a transmitting terminal device to a receiving terminal device. The teleprinters or data printers assign the character code words which are transmitted from the transmitting terminal device via a teleprinter or data network to the receiving terminal device. The code words can consist, for example, of teleprinter characters coded in accordance with the internationally standardised code CCITT No. 5.

Telecopiers, also known as facsimile devices are also known for transmitting characters or graphic patterns. However, when characters are transmitted by means of telecopiers, the characters are not coded character by character, but the graphic pattern of the character shape is transmitted. In a transmitting terminal device, a format provided with the characters is scanned line by line. In dependence upon the brightness of the format along the line data words are produced which are transmitted to the receiving terminal device where the characters are represented line by line in accordance with the scanning.

In order to transmit characters from a terminal device operating with character by character coding, for example a teleprinter, to a pattern-orientated terminal device, for example a telecopier, it would be conceivable to print out the characters on the teleprinter, to scan the document in a telecopier and to transmit it to another telecopier serving as receiving terminal device. However, this type of transmission of characters is complicated and time consuming.

Therefore the aim of the invention is to provide an arrangement with which characters input by means of a terminal device operating with character by character coding can be transmitted in a simple fashion to a pattern-orientated terminal device.

According to the present invention there is provided a communications system comprising a first communications network in which, in use, characters to be transmitted are represented by code words which code the characters character by characters, a second communications network in which, in use graphic patterns to be transmitted are represented by data words which describe the graphic patterns line by line, and a converter having an input connected to the first network and an output connected to the second network and including a character generator operable to convert said code words into corresponding data words describing the graphic patterns of the characters represented by the code words, whereby characters transmitted from a transmitting terminal of the first network can be received by a receiving terminal of the second network.

Thus a direct connection can be established between a terminal device operating with character by character coding and pattern-orientated terminal devices. Thus a pattern-orientated terminal device can be fed not only with characters or graphic patterns from a likewise patternorientated terminal device but also from a device operating with character by character coding. Consequently the characters transmitted to the patternorientated device need not necessarily be in the form of scannable formats but can be directly input by means of the keyboard or can be stored in the form of code words on data carriers, such as for example punched strips, magnetic tapes or magnetic discs.If the transmitting subscriber station possesses both a terminal device operating with character by character coding and a pattern-orientated terminal device, the characters can be input for example with the aid of the terminal device operating with character by character coding whilst associated other graphic patterns, such as pictures or drawings, are input with the terminal device operating in patternorientated fashion.

If the graphic patterns are reproduced by individual lines in the receiving terminal device, it is advantageous for each data word emitted by the character generator to be assigned to one line of a character.

If the characters are represented row by row or column by column in the receiving terminal device, the converter can contain a store in which the code words assigned to the characters of at least one row or column can be stored and which, at its output, emits the code words consecutively to the character generator until all the lines of the row or column have been represented.

If, for reasons of outlay, the graphic patterns of the characters are stored in a coarse point raster in the character generator, and the representation in the receiving terminal device is affected with a high resolution, the converter can contain an interpolation stage which produces a fine raster from a coarse point raster stored in the character generator.

In order to achieve a high transmission speed for the characters, it is advantageous for the converter to be followed by a switching stage which reduces the redundancy of the data words.

If the characters input with the aid of the transmitting terminal device are to be stored on a micro-film, one can provide a microfilm recording device as receiving terminal device.

In the following an exemplary embodiment of the arrangement corresponding to the invention will be described making reference to drawings in which: Figure 1 is a block circuit diagram of the arrangement, Figure 2 illustrates the representation of a character to be transmitted by means of code words and data words and Figure 3 is a circuit diagram of a converter provided in the arrangement.

The arrangement illustrated in Figure 1 contains two terminal devices Dl and D2 which operate with character by character coding and pattern orientated terminal devices Fl and F2. The terminal devices Dl and D2 are connected to one another via a transmission link ZC which forms part of a network via which the characters are transmitted by means of code words CW.

This network consists, for example, of a teleprinter network or data network. The terminal devices D1 and D2 are data stations which for example are of similar construction. The data stations Dl and D2 each contain, for example, a teleprinter or data printer and a data viewing device DS, or are designed as text processing devices.

In the data station Dl the characters are input with the aid of a keyboard TA or with the aid of a store SP, which may for example utilise a punched tape or a magnetic recoiling medium. By means of a control unit STI the data station produces code words CW with which the characters are coded for example in accordance with CCITT code No. 5. These code words CW are emitted to the transmission link ZC. The input characters can be represented in the data station Dl with the aid of a printer DR or a viewing device SG. Characters received via the transmission link ZC and coded by code words CW can also be output in the data station Dl by means of the printer DR and/or the viewing device SG. Received code words can also be stored in the store SP. The data stations Dl and D2 can thus be used both as transmitting terminal devices and as receiving terminal devices.However, in the following description the data station D1 will be considered merely as a transmitting terminal device.

The terminal devices Fl and F2 are pattern orientated terminal devices and for example represent telecopiers which are of similar construction. Using an input unit EG, a format provided with graphic patterns is scanned line by line for example in the telecopier Fl. In dependence upon the brightness of the format along the line, data words DW assigned to the graphic pattern along the scanned line are produced in a control unit ST2. The data words DW are transmitted to the telecopier F2 via a transmission link MC which forms part of a facsimile network. The telephone network via which the data words DW are transmitted with the aid of line matching units (not shown), such as for example modems, is frequently used as a facsimile network. If data words DW representing graphic patterns are transmitted to the telecopier Fl, these pass to the control unit ST2 which emits bright/dark signal to an output unit AG. The bright/dark signals serve to operate a reproduction element which represents the graphic patterns line by line. Thus the telecopier Fl is suitable for use both as a transmitting terminal device and as a receiving terminal device.

However, in the following description the telecopier Fl is assumed to operate only as a receiving terminal device.

If characters are to be transmitted from the data station Dl to the telecopier Fl, the code words CW emitted from the data station Dl are supplied to a converter UM.

The converter UM produces data words DW which describe the graphic patterns of the characters coded by the code words CW and emits these via the transmission link MC to the telecopier Fl. The converter UM stores for example the code words CW of the characters of one row of a text. The data words DW then consecutively indicate the graphic patterns of the characters, split into individual lines, within the row. In the telecopier Fl' the characters are represented line by line in the same way as other graphic patterns transmitted by the data words DW.

In order to achieve a high-speed transmission of the characters across the transmission link MC, the converter UM can be followed by a switching stage (not shown) which reduces the redundancy of the data words DW.

The illustration in Figure 2 has been based on the assumption that in a row, only the character "E" is to be transmitted from the data station Dl to the telecopier Fl. The character is input for example by means of the keyboard TA. The keyboard TA produces a parallel-coded code word which consists of seven bits and which is fed to the control unit STI. The control unit STI switches through a serial-coded code word CW containing the binary characters 100101, in accordance with CCITT Code No. 5 to the output of the data station D1. This code word CW is fed to the converter UM. The converter UM contains a character generator in which the graphic patterns of the characters to be transmitted are stored by means of data words DW. For example. each graphic pattern of a character is stored by means of seven data words each comprising five binary characters.In the event of row by row representation of characters in the telecopier Fl, the seven data words DW illustrated in Figure 2 are consecutively transmitted from top to bottom to the telecopier Fl. If the data words contain a binary value 1, a reproduction element is actuated in the output unit AG of the telecopier Fl and the character "E" is output.

If several characters are represented in one row, the corresponding code words CW are consecutively fed to the converter UM.

In the converter UM the data words DW assigned to one line of the row are then consecutively read out from the character generator so that the row is also represented line by line.

The converter UM illustrated in Figure 3 contains a serial-to-parallel converter SPU which is fed with the serial-coded code words CW from the data station Dl via the transmission link ZC. Under the control of a control unit ST3, the serial-to-parallel converter SPU produces parallel-coded code words which it emits to a store SPI.

The parallel-coded code words of a row, of a column, or of an entire page are intermediately stored in the store SPI. The output of the store SP1 is connected to a character generator ZG which assigns the data words which describe the graphic pattern of the characters to be transmitted to the code words. Under the control of the control unit ST3 these data words are emitted as parallel-coded data words and fed to a parallel-series converter PSU. From its output, the parallel-series converter PSU emits serial-coded data words DWI to a line matching unit LA which itself emits the serial-coded data words DW to the telecopier Fl via the transmission link MC.

The converter UM contains a switching stage SZ which is controlled by the control unit ST3 and which produces synchronising characters required for the operation of the telecopier Fl. These synchronising characters are emitted for example at the end of each line via the line matching unit LA.

If, for reasons of storage costs, the graphic patterns of the characters are stored merely in the form of a relatively coarse point raster in the character generator ZG, and the characters are required to be output with a high resolution to the telecopier Fl, the converter UM can contain an interpolation stage which produces a fine raster suitable for graphic representation by means of an interpolation process.

When a micro-film recording device is employed in place of a telecopier Fl or F2, texts drawn up in the data station Dl can be stored in a simple manner if the data words DW emitted from the converter UM are used, in place of the reproduction element in the telecopier, to control the brightness of a recording beam which is conducted line by line over a micro-film material.

WHAT WE CLAIM IS: 1. A communications system comprising a first communications network in which, in use, characters to be transmitted are represented by code words which code the characters character by character, a second communications network in which, in use, graphic patterns to be transmitted are

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. which represents the graphic patterns line by line. Thus the telecopier Fl is suitable for use both as a transmitting terminal device and as a receiving terminal device. However, in the following description the telecopier Fl is assumed to operate only as a receiving terminal device. If characters are to be transmitted from the data station Dl to the telecopier Fl, the code words CW emitted from the data station Dl are supplied to a converter UM. The converter UM produces data words DW which describe the graphic patterns of the characters coded by the code words CW and emits these via the transmission link MC to the telecopier Fl. The converter UM stores for example the code words CW of the characters of one row of a text. The data words DW then consecutively indicate the graphic patterns of the characters, split into individual lines, within the row. In the telecopier Fl' the characters are represented line by line in the same way as other graphic patterns transmitted by the data words DW. In order to achieve a high-speed transmission of the characters across the transmission link MC, the converter UM can be followed by a switching stage (not shown) which reduces the redundancy of the data words DW. The illustration in Figure 2 has been based on the assumption that in a row, only the character "E" is to be transmitted from the data station Dl to the telecopier Fl. The character is input for example by means of the keyboard TA. The keyboard TA produces a parallel-coded code word which consists of seven bits and which is fed to the control unit STI. The control unit STI switches through a serial-coded code word CW containing the binary characters 100101, in accordance with CCITT Code No. 5 to the output of the data station D1. This code word CW is fed to the converter UM. The converter UM contains a character generator in which the graphic patterns of the characters to be transmitted are stored by means of data words DW. For example. each graphic pattern of a character is stored by means of seven data words each comprising five binary characters.In the event of row by row representation of characters in the telecopier Fl, the seven data words DW illustrated in Figure 2 are consecutively transmitted from top to bottom to the telecopier Fl. If the data words contain a binary value 1, a reproduction element is actuated in the output unit AG of the telecopier Fl and the character "E" is output. If several characters are represented in one row, the corresponding code words CW are consecutively fed to the converter UM. In the converter UM the data words DW assigned to one line of the row are then consecutively read out from the character generator so that the row is also represented line by line. The converter UM illustrated in Figure 3 contains a serial-to-parallel converter SPU which is fed with the serial-coded code words CW from the data station Dl via the transmission link ZC. Under the control of a control unit ST3, the serial-to-parallel converter SPU produces parallel-coded code words which it emits to a store SPI. The parallel-coded code words of a row, of a column, or of an entire page are intermediately stored in the store SPI. The output of the store SP1 is connected to a character generator ZG which assigns the data words which describe the graphic pattern of the characters to be transmitted to the code words. Under the control of the control unit ST3 these data words are emitted as parallel-coded data words and fed to a parallel-series converter PSU. From its output, the parallel-series converter PSU emits serial-coded data words DWI to a line matching unit LA which itself emits the serial-coded data words DW to the telecopier Fl via the transmission link MC. The converter UM contains a switching stage SZ which is controlled by the control unit ST3 and which produces synchronising characters required for the operation of the telecopier Fl. These synchronising characters are emitted for example at the end of each line via the line matching unit LA. If, for reasons of storage costs, the graphic patterns of the characters are stored merely in the form of a relatively coarse point raster in the character generator ZG, and the characters are required to be output with a high resolution to the telecopier Fl, the converter UM can contain an interpolation stage which produces a fine raster suitable for graphic representation by means of an interpolation process. When a micro-film recording device is employed in place of a telecopier Fl or F2, texts drawn up in the data station Dl can be stored in a simple manner if the data words DW emitted from the converter UM are used, in place of the reproduction element in the telecopier, to control the brightness of a recording beam which is conducted line by line over a micro-film material. WHAT WE CLAIM IS:

1. A communications system comprising a first communications network in which, in use, characters to be transmitted are represented by code words which code the characters character by character, a second communications network in which, in use, graphic patterns to be transmitted are

represented by data words which describe the graphic patterns line by line, and a converter having an input-connected to the first network and an output connected to the second network and including a character generator operable to convert said code words into corresponding data words describing the graphic patterns of the characters represented by the code words, whereby characters transihitted from a transmitting terminal of the first network can be received by a receiving terminal of the second network.

2. A communications system according to claim 1, in which the first network is a teleprinter- or data-network and the second is a facsimile network or a telephone network having facsimile devices connected thereto.

3. A communications system according to claim 1 or 2, in which the characters are each graphically represented by individual lines in the receiving terminal device, and a data word emitted from the character generator is in each case assigned to one line of a character.

4. A communications system according to claim 1, 2 or 3, in which the converter contains a store in which the code words assigned to the characters of at least one row or column can be stored and which, from its output, consecutively emits the code words to the character generator until all the lines of the row or column have been represented.

5. A-communications system according to any one of the preceding claims, in which the converter contains an interpolation stage which produces a fine raster from a coarse point raster stored in the character generator.

6. A communications system according to any one of the preceding claims, in which the converter is followed by a switching stage which reduces the redundancy of the data words.

7. A communications system according to any one of the preceding claims, in which a micro-film recording device is provided as receiving terminal device.

8. A communications system substantially as herein described with reference to the accompanying drawing.