DE2842068A1 - DATA PROCESSING DEVICE - Google Patents

Description

Dipl.-Phys. O.E. Weber D-8 Monks 71

Patent attorney Hofbrunnstrasse 47

Telephone: (089) 7915050

Telegram: monopoly weaver coins

M 909

MOTOROLA, INC.
East Algonquin Road
Schaumburg, 111. 60196
United States

Data processing equipment

909814/0992

The invention relates generally to a data processing device and relates in particular to a data processing device with mobile or movable data terminals. The invention also relates to programmable mobile data terminals, which are used to send and receive in specified Wisely formatted, digitally encoded messages are appropriate.

Mobile data terminals are described, for example, in US Pat. No. 3,889 described. In these known data terminals, a circuit is available which is dedicated to the purpose of a specific Function. These circuits, which each serve a specific purpose, are used, for example, to Keyboards to operate and to scan, to display characters on a screen, to receive messages or messages to send out. Each of these circuits is independent of the other circuits. This leads to relatively complicated, unreliable and complex data terminals, which are unsuitable for use in those places where little space is available. For example, such known data terminals are not suitable for use in one Police patrol car.

The invention is based on the object of a data processing device of the type mentioned in more detail at the beginning, which is characterized by an extremely compact structure a versatile use and in particular characterized by a flexible application of their assemblies.

The patent application in particular serves to solve this problem laid down characteristics.

90981 A / 0992

According to a particularly preferred embodiment it is provided that an electronic matching subsystem is provided is to send and receive coded messages that there is also a keyboard subsystem that a character display subsystem is further provided and a programmable microcomputer subsystem is provided is to add the keyboard and pointer subsystem control and process the received and transmitted messages, and that the programmable microcomputer subsystem a program controlled in sequential order, which has a priority interrupt to the process received and transmitted data in response to a transmit and a receive system clock signal.

The invention is described below, for example, with reference to FIG Drawing described; in this show:

Fig. 1 is a block diagram of the most essential elements of a microcomputer controlled according to the invention Data terminal,

Fig. 2 is a flow chart of a microcomputer controlled Data terminal,

Fig. 3 is an illustration of the format of the message which is used by a system according to the invention,

Fig. 4 is a flow diagram of a cyclic according to the invention Redundancy character calculation routine,

5 ^{a shows} a flow chart of a transmission signal control number routine according to the invention,

5T is a flowchart of a receive control signal number routine according to the invention;

6 shows a flow chart for a further processing and control routine for explaining the invention;

9098U / 0992

Fig. 7 is a flow chart showing the status line on the Data terminal according to the invention,

Fig. 8 is a flow chart for the terminal memory display routine;

9 shows a flow chart for a data terminal time base determination according to the invention;

10 shows a flow chart for the pseudo-random sampling routine according to the invention;

Fig. 11 is a flow chart of the terminal microcomputer back-up of the present invention tartrout ine,

Fig. Ir? a flow chart for the terminal keypad scanning routine according to the invention,

Fig. 1; ') a flow chart of the combined according to the invention Carriage return and tabulator functions,

14 shows a flow diagram of the data terminal storage control routine _{t according to the invention}

Fig. 1S is a flow chart of the terminal sequential key routine;

16 is a flow chart of the terminal status line clear routine and

Fig. 17 is a flow chart of the invention. Data terminal emergency switch activation routine.

In Fig. 1 is a general overview of the invention Circuit arrangement illustrated. The embodiment of the subject matter of the invention described here contains circuit parts, which are arranged on different circuit boards and their individual components, which are shown within dashed lines in FIG are labeled accordingly to facilitate understanding. A microprocessor board 10 has a

909814/0992

- Tr - Λ

conventional arrangement of a microcomputer, preferably the structure of the microcomputer "Motorola MC6800". The microcomputer is also referred to below by the abbreviation MPU. The microcomputer MC6800 has a microprocessor unit 11, which according to the schematic representation in the drawing via a multi-line connection 12 with a plague memory (ROM) 13 is connected, which contains stored program steps that define the operation of the microprocessor unit 11. Furthermore, a multi-line connection 14 operating in two directions is connected to the microprocessor unit 11, to which a random access memory (RAM) 15 is connected which is used for the temporary storage of information by the microprocessor unit 11. On the Microprocessor board is also a circuit which is used to identify a specific data terminal, and this circuit, designated ID 16, is connected via a line 17 to the microprocessor unit. Furthermore are with the microprocessor unit via a multi-line connection 18 working in two directions, three programmable adapter adapters connected, which are designated with PIA 20, 21, 22 and also part of the microprocessor family of the type Motorola MG6800 represent. These circuits are connected to further circuits via signal lines 20a to 20g or 21a and 22a tied together. The programmable adapting adapters designated with PIA carry signals either from the microprocessor unit 11 or be sent to this unit. A $ 2 keyboard adapter is included with the programmable adapter 20 connected via signal lines 2Of working in two directions «3pi, ne energy supply circuit 30 is used to to deliver properly, stabilized or regulated supply voltages for the circuit arrangements, as symbolically is illustrated by an output line 31.

The printed circuit board labeled 40, which is the radio matching electronics subsystem records, which is also called an X / R disk or

909814/0992

is referred to as a transmitter / receiver plate, has a clock source 41, which appropriate output signals on a signal line 42 supplies to the microprocessor unit 11 and supplies further clock output signals on the signal lines 41a to 41d. A transmitter circuit 43 is with the microprocessor unit 11 via the programmable adapter 20 via the signal line 20a and with the point system via which the mobile data terminal is supplied, connected with the aid of a signal line 44. A talk and time off circuit 45 is connected to the microprocessor unit directly via a signal line 46 and indirectly via the programmable adapter connected via a signal line 20b, and it is also connected to the point system via a signal line 47. A Lock detector 48 and a receiving circuit 50 are connected to the Radio receiving device connected via a signal line 51. Both circuits are connected to the microprocessor unit 11 via signal lines 20c, 20d and 20e.

The keyboard adapter circuit 23 is connected to the keyboard 52 via a multiline signal connection 53 is connected, which input signals from the keys labeled 54-.

Characters on a visual display or screen 60, such as one from Burroughs Corporation produced alphanumeric self-scanning screen are through a multi-line signal connection 61 from a Display matching circuit 62 which is provided via bi-directional multi-line signal connections 20g and 21a, via the programmable adapters from the microprocessor unit 11 is fed. A preferably provided circuit 63, which is provided for system expansion feeds a signal line 64 and is via a signal line 22A via the programmable adapter 22 connected to the microprocessor unit 11.

9098U / 0992

ΛΛ

On the X / R plate 40 is a so-called dead man circuit 65 arranged, which is periodically put into a different switching state by transitions on the line 20a. If there are no changes for a certain period of time, the circuit 65 causes a reset signal, which via the Line 66 is passed to the microprocessor unit 11. this results in the microprocessor being prevented from operating indefinitely in an abnormal mode.

There is also a safety or emergency circuit on the X / R plate 4-0 67, which scans the status of an external switch connected to it via line 68. This circuit supplies a clock signal in response to one of the switching states on the via a logic combination circuit Line 20h to the programmable adapter. This creates the possibility that the emergency switch through the interruption input of the programmable adapter adapter is scanned.

In the pig. Figure 2 is a flow chart illustrating general operation the data terminal explained. The program begins at block 70 and then at block 71 causes the system to start is set. The program then goes to a decision block 72 which determines whether EXGPLG is set. As below As explained, EXCPLG is set after a predetermined number of clock interrupts have been received. if EXCPLG is not set, the program proceeds via the no decision path 73 to the key scan routine 7 ^. The program then advances to decision block 75 in which is determined whether a valid key has been pressed. If the answer is no, the program goes on path 76 in continue in a repeating loop. If the decision is yes, the program continues on path 77 to block 78, in which the key is operated. Depending on which type of button is pressed, the program either goes on the

909814/0992

Path 80 further if, for example, an alphanumeric key has been pressed, or path 81 if a memory display control key has been pressed, which leads to a memory display routine B ^ in which character bytes in different memories are exchanged. The program can also go from a service key routine 78 via path 8b to a read / write display routine 84- which is also connected via path 85 to the memory display routine. If the EXCFLG decision block 7'c '. is set, the program continues on the yes decision path 8G via the EXCLFG clear block 87. The program then proceeds to the voice identification transmission decision block 88 in which, if a voice signal is to be transmitted, the program continues via the yes path 90. If no voice signal is to be transmitted, the program continues on the Hein path 91 to the emergency signal transmission block 92, from which a yes decision puts the program on the path 9ü. A no decision causes the! Program to continue on the path ^c ) 'j to the message reception decision block 9 ^, while a yes decision is made over the path 95 to the program block which is used to process received messages and is denoted by 96, this block being connected via the path 97 to the read / write display block 84 and via the path 98 to the memory display block 8 ^ as required. If no message has been received, the program continues on no decision path 100. After the received message has been processed in the block, the program continues on path 101. Both paths feed path 102, which leads to decision block 10; 5, which determines whether the signal transmission time-out control is switched off. The purpose of this circuit is to provide a time period in which an acknowledgment signal or an acknowledgment from a base station is expected in order to retransmit the message after this period if no acknowledgment signal has been received and if the message has not been transmitted. The repetition can be for example

9098U / 0992

wisely to be performed five times. If the appropriate timing for a secondary transmission has not reached zero, the program goes to the Meg 104 to the decrement time control block 105, and the program then goes to ^{the executive output block 108 on the path 107 2} ^ ^1. The decision in the menu Resend time-out control device 103 fails so that the time has expired, the program goes on the yes decision path 112 to the decision block 113 in which it is determined whether the mobile data terminal is to transmit a message or not. If the answer is no, the program goes on path 114 to the executive exit block 108. If the mobile terminal is to transmit a message, the program goes on line 116 to block 117 in which the send flag is set and in which the sending message is being processed. This same block is also via the yes path 90 from the Sicherheitsbzw. Emergency and pin message identification transmission decision blocks. Decision block 117 is also connected to read / write display and memory display routines 119, which are similar to blocks 82 and 84. The program advances from block 117 to wait for interrupt clock block 118. After an interrupt clock signal has been received, a bit to be transmitted is provided to the transmission or transmission circuitry and the program proceeds to decision block 120 in which the decision is made as to whether the message is complete. If the answer is yes, the program proceeds on path 121 to block 122 in which the time stamps are set, if necessary, and the transmit flag is cleared. The send flag was set in block 117. If the decision is no, the program continues on path 123 and loops back to block 118 to await another interrupt clock signal.

909814/0992

The clock interrupt block 130 is activated when a clock pulse is received according to the transmit and receive data clock signal. This signal interrupts the program like it does described above and the microprocessor will stop and then process the clock interrupt routine. The program goes to EDGCNT decision block 15 * 1, in which determines whether a predetermined count N has been reached, if the count has not been reached, the program goes on path 132 to increment EDGCNT decision block 133-if the decision is made, the program works path 134 to EXCFLG set block 135 'and from there it goes Program to EDGCNT clear block 136. Note that EXGFLG is set after a predetermined period of time has elapsed is (determined by N clock interruptions). Setting EXCFLG results in the message processing routines run, which are entered via the path 86, as described above. During the period in which EXGFLG is not set, the key scan routines 74 are repeated served. The program then goes to the transfer mark decision block 137 »which one hit in block 117 Asks for decision. If the answer is no, the program continues on path 138 to block 140 in which a single received bit is processed. If the answer is yes, the program goes to block 142 in which a single transmission bit is processed. The program then returns to the main program via return block 143. Since the clock interrupt routine which is passed from block 130 via block 143, in the logic diagram of the microprocessor As soon as a clock interrupt signal occurs, the microprocessor will stop executing the key scan or priority of the sending and receiving programs in order to process a received or a sent bit. It is to be noted that if the send flag is not set, the arrangement processes a received bit for each clock interrupt pulse. Often times, the received bit may not be a message information bit be, but the system makes this decision,

909814/0992

after this bit has been processed with other received bits,

Ig in the i "-j. Is illustrated a representation of a formatted Dafcenendstellen-receiving or -Sendenachricht. The signal format is very similar to that format, which the Applicant is described in US-PS -j 906 4-4-5. The The content of this patent specification is hereby expressly declared to be the content of the present description. The data message according to FIG. each message transmission being interleaved with the other such that one transmission is delayed from the other by 64 bits, as described in the above-referenced patent.

The 16 identification bits are included twice in the message. Each of these 16-bit identification data fields defines a specific mobile unit and the bits are set by mechanical switches in a mobile data terminal.

The four-bit status data field of a mobile unit's message represents 16 different possible types of operations that a mobile unit can be carried out, for example that the unit is available that the unit is on the move is that the unit is in use, that the unit is out of service or that the operator is outside the vehicle. When a transmission from a base station to a mobile station, for example, the status data field is used to request that a message be sent to the mobile printer in the vehicle is printed out that a message is waiting in the base station for the mobile unit or that the base clears the display in the mobile unit.

909814/0992

The four-bit data request field is provided by a mobile data terminal to a .Bas is station to the base station for example to inform that a text message, a confirmation message or a predetermined message such as a vehicle registration check, a driver's license check, a police check, a parking violation or a traffic offense is sent. The mobile data terminal also uses this data field to inform the base station that there is another message for the base station, that a voice signal should follow, that an emergency situation exists and that a new status has occurred at the data terminal. When the base station to the mobile data terminal sends, it uses the four-bit data request field to inform the mobile unit that the message a high priority message is that a manual confirmation is required and that a status change is required the mobile data terminal is necessary. The Text / ACK two-bit data field identifies the signal as a non-text message, a text message, or a normal one Confirmation or acknowledgment signal. This data field can also be used to indicate that the message is error-free was received, but that the text could not be stored in the receiving memory because it was occupied.

The text data field consists of N six-bit bytes, where N runs from 0 to 239. If there is an alphanumeric display, a text message can be displayed in six lines of forty characters each, except for the last line, which has 39 characters contains. The interpretation of four of the characters has been changed from the usual ASCII interpretation to four to have new control characters available. These control characters are a toggle protection character PT, a flashing toggle character BT, a carriage return character CH and a runner positioning character CP. The toggle protection symbol PT informs a mobile data terminal that a message received from this base station

9098U / 0992

is either protected or unprotected, i.e. that the mobile data terminal can change certain character fields within the received message. Messages received without a toggle protection character PT in it are defined as protected, and these messages cannot be changed. The first PT character in a message field determines that all subsequent characters will be changed can be. The next PT character that appears changes the character field after these characters in such a way that the following Characters are unprotected characters. If the PT mark is displayed at a data terminal, it is considered protected Shown as a space or as a spacer. The flashing toggle character BT delivers flashing characters to a mobile data terminal, indicating that these characters are specially protected characters. If no BT mark is supplied the message is presented as a non-flashing message. BT characters in a message are represented as spacer characters. The carriage return signal CR causes the insertion of spacers at the end of the line in which it occurs. The carriage positioning character CP equips one a message received from a mobile data terminal with a runner who can be entered at any point within the changeable Part of the message can be arranged. Without a CP control character the runner is positioned at the first changeable point. If the CP character is within a protected Is placed, it is replaced with a non-breaking space, and a runner appears at the beginning of the next unprotected data field on the screen. The last runner positioning mark in a message that has been received also provides a specification of the minimum number of characters, which could be changed and sent back from the mobile station to the base station.

The six-bit stop character occurs in both text messages also in non-text messages, but not in confirmation or acknowledgment signals, and it has a message format which is compatible with previous data terminals as described in

9098U / 0992

Αϊ

the US-PS '■) 906 W? are described.

The six-bit character data field with the control number is a message identifier which is used for this purpose to prevent a base station or a mobile receiving station from duplicating the same message. Each message source independently assigns a tax number to a message sent by this point. As soon as a data terminal is activated, the tax number becomes set to zero. Each new tax number then increases the tax number by one. A retransmission of a message increases the tax number is not.

The cyclic redundancy check byte data field contains data bytes with two to six bits, which are either from the identification, status, request, text / AGK, text, stop and tax number data field be calculated. If a message is an acknowledgment or acknowledgment signal, then the message will not be cyclical Redundancy check bytes added. A cyclical redundancy check byte is calculated by first setting the cyclic redundancy check byte equal to zero and then for each Byte of data a new cyclic redundancy check byte is calculated by placing each data byte in an exclusive OR element is linked with the previously calculated cyclic redundancy byte. The cyclical redundancy check bytes are used to check the possibility of an error in a message.

A formatted message as described above is followed by a system operating tone consisting of alternating bits of one and zero and a pseudo-random data item. This operating tone is used to set corresponding low-frequency signal paths to build up, and finally syncronization clock signals to deliver. The pseudo-random data field consists of a predetermined pattern and supplies the remaining bit clock synchronization for a recipient, and it also delivers a post

909814/0992

straightening start indicator for a recipient.

In the pig. 4- The drawing illustrates a program which is contained, for example, in a read-only memory and is used to carry out the CRC calculation. The abbreviation CRC is used for the term cyclic redundancy check. The addition of the cyclic redundancy check characters does not reduce the number of detected errors in messages which are processed to the end at a mobile data terminal This routine is entered by the executive program as indicated in block 700 and the program proceeds to decision block 701 in which it is determined whether a received or sent message is completed If so, the program goes via path ^ QZ and returns to the program as indicated by block 703. If the decision is yes, the program exits path 704 to decision block 705 which determines whether the message is a text message or just a message Confirmation of delivery. If the message is an acknowledgment of a message, the program proceeds via path 706 to block 707 where the acknowledgment message is appropriately processed and the program ultimately returns as shown by block 703. If the message is not an acknowledgment, ie a text message, the axif program proceeds on path 708 to block 710 where a bit manipulation routine is performed. The program then proceeds to decision block 711 where it is determined whether the message is a received message. If this is not the case, the program goes on path 712 to block 713 where two cyclic redundancy check bytes are appended to the end of the message transmission signal and this message is processed further. The program then continues in accordance with block 714. If the message is a received message, the program goes to block 716 where a comparison is made of the two calculated cyclic redundancy check bits with the last two bits actually received in the message. The "pro-

9098U / 0992

-yf-

λο

The program then proceeds to decision comparison block 717. If the calculated and received bits are identical, the program proceeds via path 721 to block 722 where the received Message is then processed. The program then proceeds to the main program as indicated in block 714-. If the calculated and received cyclic redundancy check bits are not identified as a turn out to be the same, the program goes to block 720 and the received message is suppressed, after which the program continues.

When a clock interrupt signal occurs, as illustrated by block 730 in Figure 4-, the routine goes to decision block 731 where it is determined whether the transmission mark or send mark has been set. If this is the case, the program goes to the block via path 732 further where a transmission bit or transmission bit is processed. The program then goes to decision block 734- where determined whether a word is complete. If not, the program proceeds via path 735 to the return block 74-7 further. When the transmission word is complete, the program goes via path 736 to block 737 where the parity bit contained therein is used for this calculation is eliminated. The program then goes to block 738 where the transmit word is ORed with the lower eight bits of the previous result of the first cyclic redundancy check byte is linked. The program then goes to block 74-0 where a shift of one bit and the bit with the least significant value is set to zero. The program then goes to decision block 74-1, in which it is determined whether the new thirteenth bit is equal to one. If so, the program goes to block 743, in which a logical OR operation is carried out in order to bring the four higher-order bits up to date. The program then goes to block 74-4-, in which for the sub-

9098U / 0992

ren eight bits of the cyclic redundancy check byte a logical one
Linking OR is carried out. If the decision is im
If block 74-1 has read no, the program also goes via path 74-5 to block 7 ^ 6, i * ^1, which brings the two cyclic redundancy check bytes up to date.

The program then returns with the aid of block 74-7.

If the transmission flag is not set, the program proceeds via path 750 to block 751 in which the received bit is processed. The program then proceeds to decision block 752 which determines whether a received
Word is complete. If that's not the EaIl, you can
Program via route 753 to return block 74-7 If it is, the program goes via route 754- to decision block 755 in which it is determined whether the word is correct. If this is not the pail, the program goes to block 756,
in which the received message is not processed further
and the program then loops back according to block 74-7. If the received word is determined to be correct, go
the program via route 787 to block 737 and the program
is then continued as described above.

In FIG. 5 ^a , an algorithm is described in the form of a flowchart which is used to generate the control number of a transmission message. This routine is triggered by the transmit or send key when that key is pressed, as defined in block 180. The message is transmitted
or sent as indicated in block 181, the program proceeding to decision block 182 in which the
The system asks whether a confirmation has come from the addressed recipient of a message. If the answer is yes, the program proceeds on line 185 to block 184 where

9098U / 0992

the message tax number is increased by one. The program then goes to control block 185 where it is determined whether the Message number is greater than hexadecimal 4-0. If the answer is no, the program proceeds via path 186 to a stop as indicated by block 187. When a Acknowledgment is not received, the program proceeds from block 182 via path 188 to another decision block 190, where it is determined whether the required number of further retransmissions of a message has been carried out. If the Message has not been repeated enough times, the program proceeds on path 191 to a decision block 192, where it is determined whether the message has been transmitted and the program then proceeds on path 193 to block 181 where the Message is retransmitted. When the message has been modified or the required number of retransmissions were tried, the program goes on the path 1 ° A to a Decision block 195 where it is determined whether the message count is zero. If it does, the Program number on line 186 to stop block 187 · if the number of messages is zero, this indicates that the data terminal has not sent a message since it has been switched on. If the message number is not zero, the message number goes via path 196 to block 184-, where the number of messages is increased by one.

According to Fig. 5 ^ of the drawing is in a flow chart illustrates how a message tax number is delivered to mark received messages. The program begins at block 200 and then goes to a decision block 201, on which it is determined whether the tax number is equal to zero. If the answer is no, the program is on its way 202 to the block 203, at which the tax number with the last received tax number is compared, and the program then goes to a block 204 at which determined whether the tax numbers match. If so, the program goes to path 205

9098U / 0992

Block 206 where the received message is deleted. The program then goes to block 207, ^a * i which an acknowledgment is sent. If the tax number is zero, the program proceeds on path 208 to decision block 209 where it is determined whether a message has been entered into computer memory if memory is available. If the message has not been saved, the program proceeds on path 210 to block 212 which requires that a signal be sent to the message source indicating the busy status, that is, that the terminal is not picking up a message at this time can. When a message is entered into the terminal's memory, the program proceeds on path 215 to block 214 where the message is processed. After processing, the program goes to block 207 where an acknowledgment message is received.

In FIG. 6, a routine is illustrated which is used to set the features of the switchover protection and the flashing switchover to execute. The routine begins at block 220, in which the blink bit is cleared, the protection bit set the runner address is deleted, the character counter is cleared and the transmission counter is cleared. The program goes to block 221 where a received character is fetched, whereby this character is marked by the character counter. The program then goes to a decision block 222, where it is determined whether the fetched character is a control character. If the answer is no, the program goes on that Path 223 to block 224 where the current blink status is added to the current character. The blinking and the Protection status of the character are added to the six information bits of a character and form the seventh and eighth bits of that. The program then proceeds to write the character into the display memory, which is indicated by block 225 of the program is indicated. The program then goes to block 226,

9098U / 0992

where the character counter is incremented and on to decision block 227 where it is determined whether the character counter is at a maximum, indicating that the end of the message to be displayed is reached; is. If the character counter is not at its maximum, the program loops via path 228 back to block 221 to fetch a new character. When the character counter erreicht.hat the maximum that l-ronramm goes deia way to a CCS. Stop - block 230. If a control character has been fetched, the program proceeds on path 231 to decision block 232 where it is determined whether the fetched character is a PT character. If the answer is yes, the program proceeds on line Z'jy to decision block 234 where it is determined whether the blink bit is set. If the dummy bit is set, the program goes on path 235 to block 236 which replaces the character with a space or space. The program then returns to block 224-. If there is a PT flag and the blink bit is not set, then the program goes on line 237 to block 238 where the toggle protection bit is set. The program returns to block 236 on path d ^l i0. If a PT token was not received, the program proceeds on path 24-1 to decision block 242 where it is determined whether a blink toggle has been received. If so, the program proceeds on path 243 to compensation block 244 where it is determined that the guard bit is set. If not, the program goes on line 245 to block 236. If the protect bit is set, the program goes on path 246 to block 247 where the toggle blink bit is set, and the program then goes on path 248 to block 236. If a flash toggle PT is not received, the program proceeds on path 250 to block 251 where it is determined whether the first rotor positioning control character has been received. If the answer is yes, the program goes on line to block 25; j where the contents of the character counter are placed in the send counter, and the program then goes on line 254 to block 06. The send counter defines the number of characters -

9098U / 0992

chen, which are transmitted from a mobile data terminal or be sent. If the fetched character is a runner positioning character CP is, the program goes on line 255 to Block 256 which enters the character counter contents into the runner address and the program then proceeds on path 257 to block 236.

In Fig. 7, the routine for calling the status of the data terminal illustrates, which is to be displayed on a line of the display device. This routine is carried out by the key dept astroutine block 260 entered from where the program moved to the decision block 261 goes where it is determined whether a valid key has been depressed. If not, the program returns to the key scan routine on path 262. If so, the program goes to the decision block 265 where it is determined whether a transfer key has been depressed. If a transfer button fails has been depressed, the program proceeds on path 264 to decision block 265 which determines whether a status line key has been depressed to display the status line on the display device. If it doesn't, you can Program on path 266 to decision block 267 where it is determined whether the clear key has been depressed. If this is not the case, the program goes on path 268 to block 270 to operate the key depression. After the button is operated, the program goes to the erasure indication block 27I, and the program then returns via block 272. if a transmit key has been pressed, the program proceeds on path 272 to block 273 where the message "TRANS" is displayed for visual display is loaded into the status display. The program then proceeds to determine if the status key was pressed, at decision block 274. If so, go the program on path 275 to block 276 where a new status is entered on the status line, and that

9098U / 0992

-X-

The program then goes to decision block 277 where it is determined whether or not the status line is displayed. If not, the program goes on line 278 to block 280 to set the STAFLG flag and clear the bottom line on the screen and clear the top five lines on the screen as well The sixth line on the screen is therefore used to indicate the status of the terminal. When the status line is displayed, the program proceeds via path 281 to return block 282 and then returns to the program. However, if the transmit key was pressed, the status key was pressed was not pressed, the program proceeds on path 283 to decision block 277 "voaä. The program then operates in the manner described above. If the cancel key was pressed, the program proceeds on path 284 to decision block 285 where it is determined whether the next message buffer is displayed on the screen If so, the program goes on path 286 to block 287 and clears the next message buffer. The program then proceeds to decision block 277 where it is determined whether the status line is being displayed and the program then continues in the manner described above. If the clear key is depressed but the next message buffer is not displayed, the program proceeds on path 288 to decision block 290 where it is determined whether the status line is displayed. If displayed, the program continues on path 291 to return as shown in block 292. If the status line is not displayed, the program proceeds on path 293 to block 271 and the display is cleared.

The above discussion showed how the status indicator line on the message display screen is controlled by keystroke. The executive routine, i.e. those program steps

9098H / 0992

which are not part of the key scan routines or the interrupt routines can also control the status line display. Block 300 indicates that this routine has been entered by the executive program, and the program proceeds to decision block 301 where it is determined whether a message is received which has a priority or a message for which manual acknowledgment is received enough. If not, the program proceeds on path ^ 0Z to decision block 303 where it is determined whether a basic acknowledgment message has been received. If not, the program proceeds on path 304 to decision block 305 where it is determined whether the fifth transmission has already expired, that is, whether the message has been retransmitted to the base five times and has not been acknowledged. If the fifth transmission has not been sent, the program proceeds on path 306 to decision block 307 where it is determined whether a text transmission key has been pressed and where it is further determined whether the display is editable or changeable. If this is not the case, the program continues on path 308 to continue according to block 310. If the text transfer key is depressed and if the display is editable, the program goes on path 311 to block ^ 1rJ where an error message is displayed on the status line. The program then goes to the decision block which determines whether the status line is being displayed. The error display provides the operating personnel with an error message if an attempt is made to address a routine that is not permitted. If a message with a priority or manual acknowledgment has been received, the program proceeds via path 313 to block 314 where a message either requiring manual acknowledgment or requiring priority is loaded into the status register. The program then goes to status display decision block 277. If a basic acknowledgment has been received, the program goes on path 315 to block 316 where an "AOk OK" message is entered on the status line

9Q98U / 0992

will. The program then continues to decision block 277, when the fifth transfer has taken place, the program goes on path 317 to block 318 where a "NO ACK" message is in the Status line is loaded and the program then goes to the status line display decision block ^ 77 next.

A routine is illustrated in FIG. 6 which serves to find either that character which is to be displayed on the screen in the position of the last character, or the memory status character. This character is not a message character and is used to indicate the status of the received messages at the data terminal, and also to indicate whether the data terminal has received a message contained therein, but which has not yet been displayed. This program is entered from the key routine, as illustrated in block 320. The program proceeds to decision block 321 where it is determined whether the status line is being displayed. If not, the program goes on path> 22 to decision block 323 where it is determined whether the design memory is being displayed. The draft memory is a secondary memory that can be used to draft or formulate a message. If the draft memory is not displayed, the program takes the path j> 2. ^l · to decision block 325 where it is determined whether auxiliary memory is being displayed. If not, the program proceeds on path 326 to block 327 which causes the character "N" to be entered in the position of the last character and the program then proceeds to decision block 328 where it is determined whether the mobile data terminal knows that a message is available at the base station for the mobile data terminal. If no message is waiting, the program goes on path 330 to block 33'1, where a runner is used if necessary. The program then goes back according to block 332. When the status line is shown on the screen, the program goes

909814/0992

on path 533 to block 334- and a character "S" loaded in the position of the last character. When the design memory is presented, the program goes to the Path 335 to decision block 336, and a character "C" is loaded in the position of the last character on the screen. If the auxiliary memory is displayed, that works Program on path 3 ^ 7 to block 338 and it becomes a character "R" loaded in the position of the last character. If any of the above three characters are in the position of the last character has been entered, the program proceeds to decision block 34-0 where it is determined whether the next Message memory, i.e. the memory that receives messages from an external source, is occupied. If so, the program goes to path 34-1 Block 34-2, and the last character is made to blink, i.e. control is such that the character is intermittent lights up. If not, the program goes to decision block 328, on path 34-2, where it is determined whether the mobile data terminal is aware that a message is waiting for it in the base station.

Fig. 9 describes a routine to determine that special transmission speed, in baud, which was selected by the maintenance personnel using the appropriate line connections. This is part of the Power-up routine for the data terminal, the routine begins at start block 350 and then runs to a block 351, which carries out a sum test for certain program steps in order to check whether the program is OK is. The program then goes to decision block 352 where it is determined whether the test was successful. If this is not the case, the program goes on path 353 to the wait condition block 354-. If the exam is successful the program goes on path 355 to block 356, and the random access memory and the programmable ones Adapters are activated. The program then goes to

9 0 9 8 U / 0 9 9 2

Block 357 'and the interrupt masking for the microprocessor is cleared after the trigger routine is completed. The program then goes to block 358 and waits on the first clock interrupt signal. When the first clock interrupt signal is received, EDGClTT is incremented, as represented by blocks 370 through $ 73. That The program then goes through block 360 which increments a counter by one. The program then goes to the decision block 361 where EDGCRT is checked. If the count is not complete is set to two, the program proceeds on path 362 to block 360 where the counter is incremented again. if EDGCNT equals two, the program proceeds on path 363 to decision block 364- where it is determined whether the counter 360 has exceeded a certain number K. When the counter has exceeded this number, the program goes on path 365 to block 366 which sets the variable which is labeled BAUD and indicates the bit rate indicated on the X / R disk 40. if the number indicated by the counter is not greater than K, the program goes on path 367 to the main program, which proceeds to block 368 so that the variable BAUD thereby remains at its initial value.

It should be noted that when the variable BAUD is being built, then the variable N of block 131 is established 2 is also established because N is determined as a puncture of BAUD such that the time period, to which EXCPLG is set, has roughly the same fixed value for all values of BAUD. The Pig. 9 also shows a block 370 to indicate that when the interrupt routine is entered, EDG CNT is incremented after block 371. It Interrupt processing then occurs as indicated in block 372, and in an appropriate step this is reversed As indicated by block 373.

Q098U / 0992

FIG. 10 shows a routine which is used to determine the pseudo-statistical message advance. The program begins at block 580 which compares a received pseudo-statistical Bit and a calculated pseudo-statistical bit. The calculated pseudo-statistical bit is carried out by a routine derived, which simulates a pseudo-random generator. The program goes to a decision block 581 where it determines whether the bits match. An up / down counter is used to keep track of the differences between to count the bits, and this counter is characterized by the designation INT CNT. If the bits match, the program proceeds via signal path 382 to the decision block 383, where it is determined whether the counter content is greater than or equal to fifty. If so, the program goes on path 384 to decision block 585 * if the Counter reading is less than 50, the program goes on Signal path 386 to block 587 where the counter is incremented by one. The program then moves to the next decision block 388, where it is determined whether the count is greater than or equal to 30. If the counter content is greater than or equal to ^ O, goes the program on path 389 to decision block 585. If the count is less than zero, the program goes on signal path 399 to block 390 and the counter is incremented. The program then proceeds to decision block 391 where it is determined whether the count is greater than or equal to zero. If so, the program goes on path 392 to decision block 385. If not, then it goes Program on path 393 to block 394 where the counter increments will. It can be seen that when the bits correspond to each other, the number by which the counter is incremented, is a non-linear function of the current count. Similarly, if the bits are not equal to each other are taken, the program path 395 is taken in order to decrease the counter using appropriate decision blocks, if necessary,

909814/0992

2642068

depending on whether the corresponding counter contents are less than or equal to -50, -30 or 0. Decision block 385 determines whether the absolute value of the counter is less than or equal to 25. If this is the case, then you can Program on path 396 \ further to the next expected bit using the last bit received and the program then goes to the end block 397 * if the absolute value is not less than or equal to 25, the program proceeds via path 398 to block 400 where the next expected bit is calculated using the last bit calculated and the program then goes to block 401 where the the last calculated seven bits are compared with the previously received seven bits. Decision block 402 tests the comparison. If the bits are not the same, the program proceeds via path 403 to end block 397 * If the bits are equal, the program goes on path 404 to block 405, i.e., the reception start routine. When the receive routine has started the program has determined sufficient proportions of the proper pseudo-random sequence which are received became.

Fig. 11 illustrates a routine for determining whether the microcomputer has failed. A dead-man timer circuit is arranged on the plate 40 designated by X / R , which starts the microprocessor again if it is not supplied with logical transitions in a periodic sequence or is subjected to switching signals. The program routine described in FIG. 11 is triggered at certain times by logical transitions in the program sequence which come from the dead man circuit. The transmitted data output signal is used as a switching signal. In a non-maskable interrupt routine, as shown by block 410 and block 411, a flag designated XMTFLC is set, and that

§09814 / 0992

The program then returns through block 412. Block 413 determines, using decision block 414-, whether the flag XMTi ¹ LT has been set. If this is not the EaIl, this indicates that the processor is not processing transmitted bits, but is processing received bits, as indicated by path 415 ^to block 416. If the flag is set, indicating a transfer, the program proceeds via path 417 to block 418 where the next bit to be transferred is processed. In either case, the program returns from the interrupt routine, as indicated by block 420. During the main program, in a manner similar to decision block 72 of FIG. 2, decision block 421 tests whether the executive program flag is set. If not, the program proceeds via the key scan routine on path 422 to block 423. The program then proceeds to block 424 which contains the toggle circuit for the dead man timing circuit. The program then continues to operate the keys as indicated by block 425. If the EXC FLG flag is set, the program proceeds on path 426 to decision ^{block 427 where it is} determined whether a message has been received, in a manner similar to block 94 of FIG the message is processed by the block via path 430. If the message was not received, the signal is taken via path 431 to decision block 432, which is also entered after the received message is processed by block 428. In block 432 it is determined whether a mobile data terminal is to transmit. If not, the program returns via path 433 to the key scan routine. If the mobile station is to transmit, the program proceeds on path 434 to block 435 where a transmit on delay is created. The program then waits for an interrupt

9098U / 0992

signal as illustrated by block 436. A such an interrupt signal occurs either at the end of the Time delay of block 410 or in the form of the system clock interrupt of block 4-13. If an interrupt occurs, the program goes to block 4-37j where it is determined whether a flag XMT FLG is set. If not, the program goes on path 4-38 to block 440, and the transmission output is switched. If the XMT FLG flag is set, the program goes on the way 441 to decision block 442 where it is determined whether the transmission message is complete. If this isn't the If so, the program continues on path 443 to await an interrupt in accordance with block 436. If the Message is complete, the program proceeds on path 444 to block 445, the XMT FLG flag is cleared, and the program returns to the key scan routine.

Referring to Figure 12 of the drawings, a key scan routine is illustrated. Block 450 begins the program which advances to block 451 and the unlock and key sample counters are cleared. The program then works to decision block 452 where, as described above the EXC FLG mark is checked. If the flag is set, the program goes on path 453 to block 454, and the executive program is executed and the flag is cleared. If the checkmark is not set, the program goes on path 455 to block 456. The next Key switch is read in. The program then proceeds to decision block 457 where it is determined whether the key switch is closed is. If so, the program proceeds on path 458 to block 460 which is an external Incremental counter showing key presses. After this increase has taken place or when the Key switch is not closed, the program has gone to block 462 on path 461, the counter is incremented.

9098U / 0992

The program then goes to decision block 463 where it determines is whether the count is the same. 80 is. If it doesn't the program loops back to block 456 on path 464. If so, the program goes on path 465 to block 466 and the dead man timer output is toggled. The program then goes to signal block 467 where it determines is whether the external counter of block 460 has a count of zero. If so, the program goes Return to the beginning block 450 on route 468. If not is the case, the program goes on path 470 to decision block 471, where it is determined whether a locking or Unlocking condition is present, so that the same key depression is prevented from being operated again, namely as Result of the fact that a key switch uncertainty is set. If so, the program goes on path 472 to Block 473 and the counter of block 462 and the counter of block 460 are cleared and the program advances to the decision block 452 returns. If there is no locking or unlocking is set, the program goes on path 474 to Decision block 475 where it is determined whether the count is of block 460 is equal to one. If not, the program goes on path 476 to block 450. If so, the program goes to block 450 If so, the program goes on path 477 to block 478, and the sample counter is incremented. The program then proceeds to block 480 where it is determined whether the sample count is a predetermined one Number equals. If not, the program proceeds on path 481 to decision block 452. If so if so, the program proceeds on path 482 to decision block 483 where it is determined whether the same key applies to all Samples is depressed. If not, the program loops back to header 450 on path 484. If so, the program goes via path 485 to block 486 and the lock or unlock is set, and the program then advances to block 487 for a key operation.

909814/0992

13 illustrates a routine for performing the carriage return / tab function. The program begins at decision block 490 where it is determined whether the display has protected fields of information. If so, the program proceeds on path 491 to decision block 49 ^ where it is determined whether there are any non-character characters to the right of the runner on the existing line. If this is not the case, the program goes on path 493 to block 494, and the runner is brought to the first editable position on the next line, the display possibly being deleted from above. The program then goes to stop block 495. If the display contains protected fields, and if there are any protected characters to the right of the runner on the current line, the program goes on path 496 to block 497, " vüdA the runner becomes the next." editable position, if necessary past the protected field, and if necessary, the top of the display is deleted. If the display does not contain any protected fields, the program proceeds on path 498 to block 500 where it is determined whether the runner has arrived at the last line of the display. If not, the program proceeds along path 50I to block 502 where the traveler is moved to the starting position on the next line. If the runner is in an unprotected field and is located on the last line of the display, the program proceeds on path 503 to block 504 and the runner is moved to the beginning of the first line of the display.

14 of the drawings shows a routine which is used to give the operator a computer memory control and enable a memory exchange. The key operation routine in block 510 leads to a decision block 5111 where it is determined whether the status arrow key was pressed. If this is not the case, the pro-

909814/0992

gramin on the Wen 51 <- to decision block 5'U, and it is determined whether either a callback key 8th RCL (auxiliary AUX) or a formulation memory key CHP has been pressed. If this is not the case, the program goes on path 514- to a block 515 · If the status line key is pressed there goes ;; Program on the Wen 516 for £ ut:; clieidurifsblock 517 »where it is determined whether the status line is displayed. If so, the progi-urim returns to return block 519 on path S18. If not, the test goes on path 521 to block 5 ^ 2 and the flag STAFLG is set and the program continues to block 52: ' ^j ' where the data exchange routine runs, which is the last line exchanges the visual representation with a non-display direct memory information called STARAM which contains the status line information. When a memory key is pressed, the program proceeds on path 505 to decision block 506 where it is determined whether the status line is displayed on the terminal If so, the program continues on path 507 to clear the STAFLG flag, as indicated by block 508, and swaps with the last line of the representation and continues with a STARAH, the non-display permanent memory signal is ^{shown in accordance with block 1} YcVi. The status line information thus returns to STARAM and restores the original content of the display r her. The program then proceeds to decision block 525 which is where the program arrives even if the status line was displayed using the status line not displayed. If the design key is pressed, the program proceeds via path 527 to decision block 528. If it is determined that the design memory is not being displayed, the program proceeds via path 5 ^ 0 to decision block 531 where it is determined whether the auxiliary memory is being displayed . If not, the program goes via path 532 to block 53: where a flag VEWFLG is cleared. This mark indicates whether the

9098U / 0992

iliripf arigcpuf f he was depicted. The program then continues to perform an exchange, ie it exchanges the 239 screen mark with TXTRAM of the non-displayable read-only memory in order to hold the text, as indicated by the ülocl: ^. 4 is shown. The program then returns as indicated in block 5: -5. If the design key is pressed and the design memory is displayed, the program 536 returns in accordance with block 537. If the case ¹ ! ' button is pressed and when the auxiliary memory is displayed, the program goes on path 538 to block S> -vj, where a flag AUX is deleted, which indicates whether the auxiliary memory unit is displayed. "After block 54Ί, an exchange between the o9 Display characters are carried out with a RAM AUXRAM (not shown), and the program then returns. If the draft button has not been printed and if the auxiliary memory is not displayed as specified in decision block 5 ^ 9, the program goes on path 539 and on the Path ^ MZ to your development block 5 ^ y ₁ where it is determined whether the design memory is displayed. If this is not the case, the program continues on path 5 ^ 9 and the VEiVFLG flag is cleared as indicated by block 544. The £ .-. ';' 9 display characters are then exchanged for a TZTRAM non-display direct storage signal, as represented by block 5 ⁴ 5. The program then goes to block 5'ΊV. When the design memory is displayed, does the program go on path 5 ^ 6 to block 5 ^ 7? and the AUX flag is set. The program then proceeds to swap the 2.59 indicators for an AUXRAM non-display direct store signal, as represented by block 541. The program then proceeds to return block 537 · If the Draft button is not depressed and when the auxiliary memory is displayed, the program proceeds on the path 559 to the return of "block 537 on.

9098U / 0992

14- A routine is initiated when the next message key is depressed, as indicated by block 550. The program proceeds to decision block 551 where it is determined whether the received buffer memory is occupied. If not, the program goes on path 552 to block 553 "and the next message request is transmitted and the program returns to block 554-". If the receive buffer is full, the program proceeds on path 555 to decision block 556 where it is determined whether the receive buffer is being displayed. If so, the program goes on path 557 to block 558 and the receive buffer is cleared. The program then goes to block 559 where the VEWi ¹ LG flag is cleared and the 239 display characters are exchanged for TXTRAM non-display read only signals. The program goes to block 553 where another message request is transmitted. If a receive buffer is not being displayed, the program proceeds on path 560 to decision block 561 where it is determined whether the status line is being displayed. If so, the program goes on path 562 to block 563 where the STAB ¹ LG flag is cleared and to block 564 where an exchange is made with the last line of the display and a STARAM non-display direct store signal. If the status line is not displayed, the program proceeds on path 565 or after the memory swap to decision block 566 where it is determined whether the design memory is displayed. If not, the program proceeds on path 567 to block 568 where the ATJX flag is cleared and to block 569 where an exchange is made between the 239 displayed characters and an AUXRAM non-display direct store signal. In this case, and also when the design memory is displayed as illustrated by program path 571, the program goes to block 572 where the flag VEWFLG is set and to block 573 where the 239 displayed characters are against

909814/0992

TXTMM non-display direct storage signal can be exchanged. The program then loops back as indicated by block 574- is.

If the program is in the executive routine, as represented by block 575, then as shown in FIG. 14, it does Program to decision block 576> where it is determined whether a Test message has been received and saved. If so, the program goes on path 577 to decision block 578 »where it is determined whether the status line is displayed. If not, the program continues on path 580 to block 581. If a text message is not received and has been saved, the program continues on path 582 to block 581. When the status line is displayed, the program exits on path 583 to block 584, and enters The next depression of the message key is simulated and the program proceeds to block 581.

15 shows a routine for operating the next message key. The program begins with the next message key is depressed, as represented by block 590. The program continues to Decision block 591 where it is determined whether a received message is being presented. If this is the case, then you can Program on path 592 to block 593, and the received Message is deleted and a next message is requested from the base station as shown in block 59 ^. If a received message is not displayed, the program proceeds on path 595 to decision block 596 where it is determined whether the received memory is occupied. If not, the program goes on path 597 to block 594 and there will be a next message requested by the base station. If the receive memory is busy, the program goes on path 598 to Block 600 and the received message is displayed.

9098U / 0992

Referring to Fig. 16, a routine for processing an acknowledgment signal from an external source will be described. Block 610 indicates that an acknowledgment has been received and the program proceeds to decision block 611 where it is determined whether a manual acknowledgment indicator is activated. If so, the program proceeds on path 612 to decision block 613 where it is determined whether the previous message required manual acknowledgment. If so, the program goes on path 614 to block 615 ₅ where the manual confirmation indicator is cleared and the program then goes to block 616 where the microcomputer processes the confirmation state. In the same way, if the last message was not a manual confirmation and if the indicator for this is switched on, block 616 for processing the confirmation status is reached on path 617. If the manual acknowledgment indicator is not activated, the program proceeds on path 618 to decision block 620 where it is determined whether a priority wait indicator is activated. If not, the program proceeds on path 621 to block 616. If a priority wait indicator is activated, the program proceeds on path 622 to decision block 623 where it is determined whether the last message contained a request for a next message . If not, the program goes on path 624 to block 616. If so, the program goes on path 625 to block 626 to clear the message waiting indicator.

17 is an emergency foot switch activation scan routine shown. This program is entered from the executive program as shown in block 630, and proceeds to decision block 631 where it is determined whether a particular count is greater than a predetermined one Value. The determined counter reading is obtained by the interruption setting states of an interruption

909814/0992

Control registers of a peripheral adapter such as a Motorola MC 6820 circuit are counted, the interrupt status being set by the edges of the clock pulses which are activated by an emergency switch. The emergency switch is activated during the time period that is greater than the impact time of the switch. If the decision is yes, the program proceeds on path 632 to block 63 ^ ¹ where a transmit flag or send flag is set and an emergency code message is loaded. The program then goes to block 634- where the emergency message is transmitted and to block 635 where an acknowledgment timer is started. The program goes to block 636 where the transmission counter is cleared providing an ongoing transmission of the emergency message. If the switch is not activated for a sufficient time, the program proceeds on path 637 to block 638 and the program waits for a clock break indication at which time, as shown in block 640, the programmed adapter register is read if the emergency foot switch is actuated. It should be noted that the register of the programmable adapter is reset after reading. The program goes to decision block 64-1 where it is determined whether the emergency foot has been closed. If it is not the jail, the program continues on path 64-2 to clear the counter, as represented by block 64-3. If the emergency foot switch is closed, the program proceeds on path 64A to block 64-5 and the counter is incremented.

9098U / 0992

Blank page

Claims (14)

Claims (i.1 data processing device for a programmable mobile data terminal, for sending and receiving digitally coded, formatted in a predetermined manner Messages, characterized in that an electronic matching subsystem (4p, 45,48,50) is provided to send and receive coded messages that further a keyboard subsystem (23,52) is present, that a character display subsystem (62, 61) is also provided, and that a programmable one Microcomputer subsystem (11,13,15,16,20,21,22,41) is present to the keyboard and the display subsystem to control and to process the received and transmitted messages, and that the programmable microcomputer subsystem a program controlled in sequential order which interrupts priority has to process the received and transmitted data in response to a transmit and a receive system clock signal to process. 2. Device according to claim 1, characterized in that that the formatted, digitally encoded messages contain an encoded data message which is a cyclic Contains redundancy check byte. 3- device according to claim 1, characterized in that that the formatted, digitally encoded messages contain an encoded data message which is a tax number byte contains to identify certain messages. 4. Device according to claim 1, characterized in that that messages which have been received by the data terminal initially contain a control character in order to instruct the computer subsystem to designate certain characters as non-editable and continue to enter second control characters to control the computer subsystem 9098U / 0992 assign to distinguish certain characters of the non-editable characters from certain other non-editable characters. 5. Device according to claim 1, characterized in that that the ^ gauge display subsystem includes a display device which displays a series of character positions has to alternately display message characters and the operating status of the data terminal. 6. Device according to claim 1, characterized in that that there are a plurality of storage elements that the character display subsystem is a visual display having a character position dedicated to the representation of one of a plurality of characters, and that each of the plurality of characters represents a particular memory element. 7. Device according to claim 1, characterized in that that the data terminal has a device which is used to determine the value of a variable, which causes a system clock period to be the same for all pre-set system data rates Value is set. 8. Device according to claim 1, characterized in that that the messages have a pseudo-random header and that the system has programmed circuitry which is used to determine the presence of the pseudo-random header for received messages. 9. Device according to claim 1, characterized in that that the data terminal has a device which serves to control the computer-ITintersystem program sequence automatically restart if a! "ehlfunktion in the System occurs as it may be due to the absence of a switchover signal. 9098U / 0992 10. Device according to claim 1, characterized in that that the display subsystem has a runner mark, that the keyboard subsystem has a key for the alternative Positioning the runner at the beginning of the next unprotected Character group and on the next line, which has unprotected characters, depending on of which state occurs earlier. 11. Device according to claim 1, characterized in that that a plurality of storage elements are provided and that there is furthermore a device which serves to represent the contents of the memory elements in an alternative way. 12. Device according to claim 1, characterized in that that a device is provided which responds to a command of the operating personnel to a though to display a received but not displayed message, and to display a message that has not yet been received but is sent to the Base station available message to represent. 13. Device according to claim 1, characterized in that that a device for processing a confirmation signal is provided, the mode of operation of the previously messages received. 14. Device according to claim 1, characterized in that that a switch is provided, that a first circuit device is also present, which serves to To deliver clock pulses in response to a certain status of the switch that continues to be a peripheral matching adapter is provided having an interrupt register which is set in response to the edge of the clock pulses is that further a device is provided which 90 9 8 U / 0992 serves to repeatedly read the interrupt register output, and finally some means are provided is to determine whether the switch is in for a predetermined number of consecutive retry reads has been a certain status. 15 ♦ Device according to claim 1, characterized in that that the keyboard subsystem is scanned for a key closure. 9098U / 0992