CELLULAR TELEPHONE WITH STANDARD
This is a continuation of application Ser. No. 07/369,419. filed Jun. 20, 1989 and now abandoned, which in turn is a continuation-in-part of application Ser. No. 07/349,619 filed May 10, 1989 and now abandoned.
BACKGROUND OF THE INVENTION
The present invention is generally related to radiotelephones, and more particularly to a cellular telephone with a standard telephone set.
Cellular telephones currently are operated with a special purpose handset that is coupled via audio and data buses to a cellular telephone transceiver. In order to avoid use of a cellular radio channel during dialing and minimize costs of cellular telephone calls, cellular telephone users are required to dial a telephone number and then press a "SEND" button (pre-origination dialing), in order to place a cellular telephone call. Pressing the "SEND" button causes the cellular telephone handset to generate a "SEND" signal and append it to the dialed digits transmitted to the cellular telephone transceiver.
When a conventional pulse or tone dial telephone set or equivalent machine, such as a modem, is used in -10 association with a cellular telephone, there is a need for either a "SEND" button or circuitry that simulates the "SEND" function. A "SEND" button can be added to a conventional telephone set by using a # or * button or hookswitch flash, both requiring additional circuitry ^5 and/or software in an interface device.
A "SEND" button can also be simulated by detecting the end of dialing and automatically generating the "SEND" signal in the same manner as is done by the cellular telephone handset. Detecting the end of dialing and automatically generate the "SEND" signal is described in U.S. Pat. Nos. 4,658,096, 4,737,975 and 4,775,997. According to these patents, an interface device detects the end of dialing and automatically ap- 4J pends a "SEND" signal to the dialed digits sent to the cellular telephone transceiver. However, in order to detect the end of dialing, such interface device requires additional circuitry to determine how many digits the dialed telephone has and then count the number of j0 dialed digits actually received. Thus, adding a "SEND" button or circuitry that simulates the "SEND" function as in the prior art described above requires additional circuitry and increases the cost and complexity of the cellular telephone. For the foregoing reasons, there is a 55 need for a cellular telephone which does not require generation of the "SEND" signal.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention 60 to provide a unique cellular telephone for use with a standard telephone set or equivalent device, which automatically places and receives cellular telephone calls.
It is another object of the present invention to pro- 65 vide a unique cellular telephone which processes digits of a telephone number dialed in any pattern on a standard telephone set or equivalent device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a cellular telephone 100 embodying the present invention, into which a standard 5 telephone instrument 101 may be plugged.
FIG. 2 is a flow chart for the process used by microcomputer 108 in FIG. 1 for processing dialed digits of a telephone number. FIG. 3 is a flow chart for the process used by mi10 crocomputer 108 in FIG. 1 for processing incoming telephone calls.
FIG. 4 is a flow chart for the process used by microcomputer 129 in cellular telephone transceiver 109 in FIG. 1 for receiving dialed digits of a telephone 15 number and placing a telephone call to the dialed telephone number.
DETAILED DESCRIPTION OF THE
Referring to FIG. 1, there is illustrated a block diagram of a cellular telephone 100 embodying the present invention, into which a standard telephone set 101 may be plugged. Cellular telephone 100 may be advantageously utilized in remote locations for providing cellular telephone services to subscribers who can not obtain conventional landline telephone service. Telephone set 101 may be a conventional telephone instrument or equivalent device having either a pulse or tone dial. For example, telephone set 101 may be a desk set, wall set, modem, or a separate dial, ringer and handset of the type found in a phone booth. Telephone set 101 requires approximately twenty milliamps of operating current provided by cellular telephone 100 via two wires 112 typically referred to as "tip" and "ring" wires. Telephone set 101 also typically includes a modular RJ11C plug 113 which couple to corresponding modular RJUC receptacle 114 in cellular telephone 100.
Cellular telephone 100 includes a cellular telephone transceiver 109 with a radio transceiver 119 and microcomputer 129 with memory therein for controlling the operation thereof. Cellular telephone transceiver 109 may be any conventional cellular telephone transceiver having a radio transmitter, radio receiver and logic unit, such as, for example, the transceiver shown and described in Motorola instruction manual number 68P81066E40, entitled "DYNATAC Cellular Mobile Telephone 800 MHZ Transceiver," published by and available from Motorola C & E Parts, 1313 East Algonquin Road, Schaumburg, 111. 60196.
Cellular telephone 100 also includes blocks 102-106 for interfacing cellular telephone tranceiver 109 to telephone set 101. Blocks 102-107 provide the audio, voltage and dial signal interface circuitry to telephone set 101 and may be conventional circuits of the type shown and described in Motorola instruction manual number 68P81071E30, entitled "THE CELLULAR CONNECTION Cellular Mobile Telephone Intelligent RJ11C Interface," published by and available from Motorola C & E Parts, 1313 East Algonquin Road, Schaumburg, 111. 60196.
Voltage generator 107 generates a 48 V DC voltage which is coupled to wires 112 for supplying approximately twenty milliamps of current to operate telephone set 101. Ring voltage generator 106 produces a ringing signal having a high voltage at a rate commonly used in telephone systems and being coupled via voltage generator 107 to telephone set 101. The rate of the ringing signal produced by ring voltage generator 106 is