Programmable digital data terminal for mobile radio transceivers

• US 4,354,252 A
• Filed: 02/02/1981
• Issued: 10/12/1982
• Est. Priority Date: 09/27/1977
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lamb, James A., Blankenship, Johnny E., Hamilton, Kenneth W., Dykas, George E., Milleker, William
• Primary Examiner(s): Williams, Jr., Archie E.
• Application Number:
  US06/230,828
• Time in Patent Office: 617 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 364/409, 364/424, 375/7, 375/8, 455/11, 455/31, 455/38, 455/89, 455/73-78, 455/158, 179/2 DP, 179/2 EB, 179/1 VE, 179/5 R, 370/104
• US Class Current: 340/502
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00

Abstract

In a data transmission system, for communicating messages between a base station and a plurality of mobile stations, each mobile station includes a radio frequency transceiver and a programmable data terminal for sending and receiving predeterminedly formatted digitally encoded messages. A keyboard subsystem and character display subsystem are controlled by a programmable microprocessor subsystem which also processes received and transmitted messages. A transmit and receive system clock interrupts the operation of the microcomputer to process messages. The messages include a cyclical redundant check byte as well as a control number byte. Characters which are not editable blink. A terminal status display line is provided and a message received character is also provided. The system sets the system clock period to be the same for all data rates. Automatic restart of the system is provided as well as a means for detecting and generating a pseudo-random message preamble. Cursor positioning, memory interchange, and display keys are provided. Receipt and acknowledgement of various types of messages are also provided.

Claims

1. A radio frequency digital data transmission system for communicating digital messages between a base station and a plurality of mobile stations, where the mobile stations each include a radio transceiver and a programmable data terminal coupled thereto for receiving and transmitting digital messages, wherein the programmable data terminal of each mobile station comprises:

means for generating a data clock signal;

means coupled to the radio transceiver for receiving in response to the data clock signal, successive bits of digital messages transmitted from the base station;

keyboard means including a transmit key and a plurality of alphanumeric keys;

display means including a plurality of display elements for visually displaying digital messages applied thereto;

means coupled to the radio transceiver for transmitting in response to the data clock signal, successive bits of digital messages applied thereto; and

processing means including a compose memory, a next message memory, a read-only memory for storing a control program and peripheral-interface-adapter means for interfacing the processing means to the data clock signal generating means, receiving means, keyboard means, display means and transmitting means;

the processing means receiving a digital message entered from the keyboard means, storing the entered digital message in the compose memory, and applying the entered digital message to the display means; and

the processing means further having an interrupt input coupled to the clock signal and being responsive to each predetermined logical state change of the clock signal for, under control of the control program, storing in the next message memory successive bits of a digital message received by the receiving means, and, when the transmit key is activated, applying successive bits of a digital message stored in the compose memory of the transmitting means.

2. The digital data transmission system according to claim 1, wherein said display means includes a status element, said processing means enabling the status element to display a first status character when all the bits of a digital message have been received by receiving means and stored in the next message memory.

3. The digital data transmission system according to claim 2, wherein said processing means in the programmable data terminal is responsive to succeeding digital messages received by the receiving means for blinking the first status character displayed in the status element of the display means.

4. The digital data transmission system according to claim 3, wherein said keyboard means of the programmable data terminal includes a next message key, said processing means responsive to a first activation of the next message key for enabling the digital message stored in the next message memory to be applied to the display means and thereafter transmitting an acknowledgment digital message to the base station.

5. The digital data transmission system according to claim 4, wherein said processing means is responsive to a second activation of the next message key for transmitting a polling digital message to enable the base station to retransmit previously transmitted digital messages.

6. The digital data transmission system according to claim 1, wherein said programmable data terminal includes a status line memory, said keyboard means includes a status line key, and said display elements of the display means are organized into a plurality of parallel lines each having the same number of display elements;

said processing means sensing the status of pre-selected portions of the programmable data terminal and storing the sensed status in the status line memory, and said processing means enabling a predetermined line of display elements to display the status stored in the status line memory in response to a sensed change in the status from the previously sensed status and in response to an activation of the status line key.

7. A method for use in a radio frequency digital data transmission system where digital messages are communicated between a base station and a plurality of mobile stations, and where the mobile stations each include a radio transceiver and programmable data processing means coupled thereto for receiving and transmitting digital messages, said method for receiving a digital message and ignoring subsequent duplicates of the same digital message communicated between the base station and the mobile stations, said method comprising the steps of:

(a) appending control numbers to successive digital messages transmitted by the base station, wherein different control numbers are appended to different digital messages at the base station;

(b) comparing the control number of a received digital message to the control number of a predetermined number of previously received digital messages at a mobile station;

(c) accepting the received digital message if it has a different control number from that of the predetermined number of previously received digital messages at the mobile station; and

(d) discarding the received digital message if it has the same control number as that of a previously received digital message at the mobile station.

8. The method according to claim 7, wherein step (c) further includes the step accepting the received digital message if it has a predetermined control number.

9. The method according to claim 7, wherein step (a) further includes the step of consecutively numbering the control numbers from a predetermined minimum number to a predetermined maximum number.

10. The method according to claim 9, wherein said numbering step further includes the step of repeating the numbering from the predetermined minimum number when the control number is the predetermined maximum number.

11. A method for use in a radio frequency digital data transmission system where digital messages are communicated between a base station and at least one mobile station, and where the mobile station includes a radio transceiver and programmable data processing means coupled thereto for receiving and transmitting digital messages, said method for receiving a digital message and ignoring subsequent duplicates of the same digital message communicated between the base station and the mobile station, said method comprising the steps of:

(a) appending control numbers to successive digital messages prior to transmission by the base station or the mobile station, wherein different digital control numbers are appended to different messages at the base station or the mobile station, respectively;

(b) comparing the control number of a received digital message at the base station or the mobile station to the control number of a predetermined number of previously received digital messages at the base station or the mobile station, respectively;

(c) accepting the received digital message at the base station or the mobile station if it has a different control number from that of the predetermined number of previously received digital messages at the base station or the mobile station respectively; and

(d) discarding the received digital message at the base station or the mobile station if it has the same control number as that of a previously received digital message at the base station or the mobile station, respectively.

12. A method for use in a radio frequency digital data transmission system where digital messages are communicated between a base station and a plurality of mobile stations, and where the mobile stations each include a radio transceiver, programmable data processing means coupled to the radio transceiver for receiving and transmitting digital messages, a memory, a next message indicator, a visual display and a next message pushbutton, said method for enabling the mobile stations to retrieve digital messages previously communicated from the base station, said method comprising the steps of:

(a) receiving from the base station a first digital message and storing the first digital message in the memory;

(b) receiving from the base station a second digital message;

(c) actuating the next message indicator in response to receipt of the second digital message;

(d) accessing the digital message stored in the memory and displaying the accessed digital message in the visual display in response to a first activation of the next message pushbutton; and

(e) transmitting a digital message to the base station for causing the base station to retransmit the second digital message in response to a second activation of the next message pushbutton.

13. The method according to claim 12, wherein step (a) includes the step of displaying the first digital message in the visual display if it is not in use, and step (b) includes the step of storing the second digital message in the memory.

14. The method according to claim 12, further including the steps of deactuating the next message indicator and repeating steps (a), (b), (c), (d) and (e) for succeeding digital messages.

15. A radio frequency digital data transmission system for communicating digital messages between a base station and a plurality of mobile stations, where the mobile stations each include a radio transceiver and a programmable data terminal coupled thereto for receiving and transmitting digital messages, wherein the programmable data terminal of each mobile station comprises:

means for generating a clock signal;

means coupled to the radio transceiver for receiving in response to the data clock signal, successive bits of digital messages transmitted from the base station;

a keyboard including a transmit key and a plurality of alphanumeric keys;

a display including a plurality of display elements for visually displaying digital messages applied thereto;

means coupled to the radio transceiver for transmitting in response to the clock signal, successive bits of digital messages applied thereto; and

a microcomputer including a compose memory, a next message memory, a read-only memory for storing a control program and peripheral-interface-adapter means for interfacing the microcomputer to the receiving means, keyboard, display and transmitting means;

the microcomputer receiving a digital message entered from the keyboard, storing the entered digital message in the compose memory, and applying the entered digital message to the display; and

the microcomputer further having an interrupt input coupled to the clock signal and being responsive to each predetermined logical state change of the clock signal for, under control of the control program, storing in the next memory successive bits of a digital message received by the receiving means, and, when the transmit key is activated, applying successive bits of a control number and an entered digital message stored in the compose memory to the transmitting means, the microcomputer appending different control numbers to each entered digital message that is transmitted.

16. The digital data transmission system according to claim 15, wherein said base station appends different control numbers to each digital message transmitted to a mobile station, said microcomputer comparing the control number of each digital message received by the receiving means to the control number of previously received digital message and discarding the digital message received by the receiving means if its control number in the same as the control number of the previously received message.

17. A method for use in a radio frequency digital data transmission system where digital messages are communicated between a base station and a plurality of mobile stations, and where the mobile stations each include a radio transceiver and programmable data processing means coupled thereto for receiving and transmitting digital messages, said method for receiving a digital message and ignoring subsequent duplicates of the same digital message communicated between the base station and the mobile stations, said method comprising the steps of:

(a) appending control numbers to successive digital messages transmitted by the base station, wherein different control numbers are appended to different digital messages at the base station;

(b) comparing the control number of a received digital message to the control number of predetermined number of previously received digital messages at a mobile station; and

(c) discarding the received digital message if it has the same control number as that of a previously received digital message at the mobile station.