초록 ▼

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 larg

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.

대표청구항 ▼

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 hos

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.