Cellular data telephone system and cellular data telephone therefor

• US 4,837,800 A
• Filed: 03/18/1988
• Issued: 06/06/1989
• Est. Priority Date: 03/18/1988
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Dautel, Donald F., Freeburg, Thomas A.
• Primary Examiner(s): Lev, Robert
• Application Number:
  US07/170,224
• Time in Patent Office: 445 Days
• Field of Search: 379/60, 379/59, 379/58, 379/63, 455/33, 455/34
• US Class Current: 455/557
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A unique cellular data telephone system includes a cellular telephone system (CTS 150), a cellular data switch (CDS 170), and a telephone central office (130) for providing both voice and data telephone servies to portable and mobile cellular data telephone (CDTs 102, 122) located anywhere in a large geographical area. Each of the CDTs (102, 122) includes a data control unit (DCU 106), a cellular modem (162) and a cellular telephone (108) and associated antenna (110), and connects to a data terminal (104, 124) with keyboard and display. DCU (106) includes memory (302) for storing a CDS telephone number and CDT telephone number, microcomputer (304) with internal memory for controlling data communications between cellular modem (162) and data terminal (104), a dual tone multifrequency ("DTMF") encoder (306) for encoding telephone numbers and control signals, a DTMF decoder (314) for decoding DTMF telephone digits and/or DTMF control tones, a buffer (312) for storing transmit data from data terminal (104), and analog switches (308, 310) for coupling DTMF encoder (306) and buffer (312) to the transmit data Td signal to cellular modem (162). If data terminal (104) is inactive for a predetermined time interval, DCU (106) automatically disconnects the cellular telephone call while maintaining the landline telephone call to a data host (140, 141). Once data is transmitted again by data terminal (104), DCU (106) automatically places another cellular telephone call and is reconnected to the landline telephone call.

Claims

1. A cellular data telephone system for communicating data with a data host, comprising:

a cellular telephone system having a plurality of radio channels for cellular telephone calls;

a landline telephone system having a plurality of telephone lines for switching a landline telephone call to a data host;

a cellular data switch having a plurality of telephone lines coupled to the cellular telephone system and landline telephone system for switching a cellular telephone call to the landline telephone system, said cellular data switch maintaining and reswitching a cellular telephone to a switched telephone line to the landline telephone system until disconnected by the cellular telephone;

a cellular telephone having a predetermined telephone number for originating and receiving cellular telephone calls on the cellular telephone system;

a cellular modem coupled to the cellular telephone for communicating data therebetween;

a data terminal for transceiving data, said data terminal producing a call origination signal having a first state when a landline telephone call to the data host is originated and a second state when the landline telephone call is disconnected; and

data control means coupled between said data terminal and said cellular modem for coupling data therebetween, said data control means responsive to the first state of the call origination signal for placing and disconnecting cellular telephone calls to the cellular data switch depending on the data activity of the data terminal, and said data control means responsive to the second state of the call origination signal for disconnecting the cellular telephone call and the landline telephone call.

2. The cellular data telephone system according to claim 1, wherein said data control means includes buffer means for storing data from said data terminal when a cellular telephone call is disconnected and the landline telephone call is being maintained.

3. The cellular data telephone system according to claim 1, wherein said cellular data switch includes buffer means for storing data from said selected data host when a cellular telephone call is disconnected and the landline telephone call is being maintained.

4. A Cellular data telephone system for communicating data with a data host, comprising:

a cellular telephone system having a plurality of radio channels for cellular telephone calls;

a landline telephone system having a plurality of telephone lines for switching a landline telephone call to a data host;

a cellular data switch having a plurality of telephone lines coupled to the cellular telephone system and landline telephone system for switching a cellular telephone call to the landline telephone system, said cellular data switch maintaining and reswitching a cellular telephone to a switched telephone line to the landline telephone system until disconnected by the cellular telephone;

a cellular telephone having a predetermined telephone number for originating and receiving cellular telephone calls on the cellular telephone system;

a cellular modem coupled to the cellular telephone for communicating data therebetween;

a data terminal for transceiving data, said data terminal producing a call origination signal having a first state when a landline telephone call to the data host is originated and a second state when the landline telephone call is disconnected; and

data control means coupled between said data terminal and said cellular modem for coupling data therebetween, said data control means including;

buffer means for storing data from the data terminal and producing an output signal when said buffer means is full; and

processing means for placing a cellular telephone call to the cellular data switch in response to the first state of the call origination signal, for disconnecting the cellular telephone call when data has not been received from the data terminal for a predetermined time interval, for placing another cellular telephone call to the cellular data switch in response to the buffer means output signal, and for disconnecting the cellular telephone call and the landline telephone call in response to the second state of the call origination signal.

5. The cellular data telephone system according to claim 4, wherein said cellular data switch includes buffer means for storing data from said selected data host when a cellular telephone call is disconnected and the landline telephone call is being maintained.

6. A cellular data telephone for communicating data with a data host, said cellular data telephone coupled to the data host by means of a cellular telephone system, a cellular data switch and a landline telephone system, said cellular data switch having a plurality of telephone lines coupled to the cellular telephone system and landline telephone system for switching a cellular telephone call to the landline telephone system, and said cellular data switch maintaining and reswitching a cellular data telephone to a switched telephone line to the landline telephone system until disconnected by the cellular data telephone, said cellular data telephone comprising:

a cellular telephone having a predetermined telephone number for originating and receiving cellular telephone calls on the cellular telephone system;

a data terminal for transceiving data, said data terminal producing a call origination signal having a first state when a landline telephone call to the data host is originated and a second state when the landline telephone call is disconnected;

data control means coupled between said data terminal and said cellular telephone for coupling data therebetween, said data control means including;

buffer means for storing data from the data terminal and producing an output signal when said buffer means is full; and

processing means for placing a cellular telephone call to the cellular data switch in response to the first state of the call origination signal, for disconnecting the cellular telephone call when data has not been received from the data terminal for a predetermined time interval, for placing another cellular telephone call to the cellular data switch in response to the buffer means output signal, and for disconnecting tee cellular telephone call and the landline telephone call in response to the second state of the call origination signal.

7. The cellular data telephone according to claim 6, wherein said data control means further includes means for encoding an RF disconnect signal when entered data has not been received for the predetermined time interval and coupling said RF disconnect signal to said cellular telephone for transmission.

8. The cellular data telephone according to claim 6, wherein said data control means further includes means for storing the predetermined telephone number of said cellular telephone, said processing means coupling the stored predetermined telephone number to said cellular telephone for transmission when a cellular telephone call has been placed.

9. A cellular data telephone for communicating data with a data host, said cellular data telephone coupled to the data host by means of a cellular telephone system, a cellular data switch and a landline telephone system, said cellular data switch having a plurality of telephone lines coupled to the cellular telephone system and landline telephone system for switching a cellular telephone call to the landline telephone system, and said cellular data switch maintaining and reswitching a cellular data telephone to a switched telephone line to the landline telephone system until disconnected by the cellular data telephone, said cellular data telephone comprising:

a cellular telephone having a predetermined telephone number for originating and receiving cellular telephone calls on the cellular telephone system;

a cellular modem coupled to the cellular telephone for communicating data therebetween;

a data terminal for transceiving data, said data terminal producing a call origination signal having a first state when a landline telephone call to the data host is originated and a second state when the landline telephone call is disconnected;

data control means coupled between said data terminal and said cellular modem for coupling data therebetween, said data control means including;

buffer means for storing data from the data terminal and producing an output signal when said buffer means is full; and

processing means for placing a cellular telephone call to the cellular data switch in response to the first state of the call origination signal, for disconnecting the cellular telephone call when data has not been received from the data terminal for a predetermined time interval, for placing another cellular telephone call to the cellular data switch in response to the buffer means output signal, and for disconnecting the cellular telephone call and the landline telephone call in response to the second state of the call origination signal.

10. The cellular data telephone according to claim 9, wherein said data control means further includes means for encoding an RF disconnect signal when entered data has not been received for the predetermined time interval and coupling said RF disconnect signal to said cellular telephone for transmission.

11. The cellular data telephone according to claim 9, wherein said data control means further includes means for storing the predetermined telephone number of said cellular telephone, said processing means coupling the stored predetermined telephone number to said cellular telephone for transmission when a cellular telephone call has been placed.

12. A method of communicating data between a cellular data telephone and a data host, said cellular data telephone coupled to the data host by means of a cellular telephone system, a cellular data switch and a landline telephone system, said method comprising the steps of:

placing a cellular telephone call to the cellular data switch and a landline telephone call to the data host;

disconnecting the cellular telephone call when data has not been received from the cellular data telephone for a predetermined time interval;

maintaining the landline telephone call;

storing data from the cellular data telephone in buffer means until the buffer means is full; and

placing another cellular telephone call to the cellular data switch when the buffer means is full.

13. A method of communicating data between a cellular data telephone and a data host, said cellular data telephone coupled to the data host by means of a cellular telephone system, a cellular data switch and a landline telephone system, said method comprising the steps of:

placing a cellular telephone call to the cellular data switch and a landline telephone call to the data host;

disconnecting the cellular telephone call when data has not been received from the cellular data telephone for a predetermined time interval;

maintaining the landline telephone call;

storing data from the cellular data telephone in first buffer means until the first buffer means is full;

storing data from the data host in second buffer means until the second buffer means is full; and

placing another cellular telephone call to the cellular data switch when one of the first and second buffer means is full.