Note: Descriptions are shown in the official language in which they were submitted.
WO 90/14729 ;7 ~ . & r- PCI/US90/017~7
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CEI I ULAR TELE.PHONE
WITH STANDARD TELEPHONE SET
thQ~ ln~D~tiQn
The present invention is generally related to
radiotelephones, and more particularly to a cellular
telephone with a standard telephone set.
C:ellular telephones currently are operated with a'
special purp,ose handset that is ooupled 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 ~SFND~ button causes
the cellular telephone handse$ to generate a "SEND" signal
and append it to the dialed digits transrnittad to the
cellular tel0phone transceiver.
When a conventional pUI5e or tone dial telephone set
or equivalent machine, such as a modem, is used in
association with a callular telephene, there is a need for
eith~r a "SEND" button or circuitry that simulates the
~SEND" function. A "SEND~ button can be added to a
conventional telephone se~ by using a # or ~ button or
hookswiteh flash, both requiring additional circuitry and/or
software in an intarface dcvice.
A ~SEND~ button can also be simulated by d~tecting
the end of dialing and automatically generating the "SEND"
signal in the sarne manner as is done by the cellular
telephone h~ndset. 13etecting the end of dialing and
automaticaily generate the ~SEND" signal is described in US
WO 90/14729 ~ ,' P~/US90/01797
Patent Nos. 4,658,096, 4,737,975 and 4,775,997. According
to these pat~nts, an interfac~ davice det~cts the end of
dialing and automatically appends a "SEND" signal to the
dialed digits sent`to the cellular telephone transceiv~r.
5 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 dialed digits actually recaived. Thus, adding a
"SEND" button or circuitry that simulates the USEND"
10 function as in the prior art described above r~quires
additional circuitry and increases the cost and complexity
of the cellular telephone. For the foregoing reasons, there
is a need for a cellular telephone which does not require
generation of the "SEND" signal
Accordingly, it is an object of the prssent invention
to provide a unique cellular telephona for use with a
20 ~tandard tal~phone set or equivalent device, which
automatically places and receives cellular telephon~ calls.
It is another obj~c~ of the present invention to
provide a unique cellular telephone which processes digits
of a telephone number dial~d in any pattern on a standard
25 telsphone set or squivalsnt devic~.
Figure 1 is a block diagram of a cellular telephone
30 100 embodying the present invention, into which a standard
telephone instrument 101 may be plugged.
Figure 2 is a flow ohart for the process used by
microcomput~r 108 in Figure 1 for processing dialed digits
of a t~lephone numbor.
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Figure 3 is a flow chart for the proc0ss usad by
microcornputer 108 in Figure 1 for processing incoming
telephone calls.
Figure 4 is a flow chart for the process used by
5 microcomputer 129 in cellular talephone transc~iver 109 in
Figure 1 for recaiving dialed digits of a telsphone number
and placing a telephone call to the dialed telephone number.
Referring to Figure 1, thsre is illustrated a block
diagram ef a cellular telephone 100 smbodying the present
invention, into which a standard telephone set 101 may be
plugged. Cellular telephone 100 may be advantageously
15 utilized in remote locations ~or providing cellular
telephone services to subscribers who can not obtain
convantional landline telephone service. Telephone set 101
may be a conventional telephone instrument or equivalent
device having either a pulse or tone dial. For examplc,
20 tclephone set 101 may be a desk set. wall s~t, modem, or a
separate dial, rin~er and handsst of the type found in a
phona booth. Telephone se~ 101 requir~s approximately
twenty milliamps of operating current provided by cellular
telephone 100 via two wires 112 typically refarred to as
25 ~tip~ and ring" wires. Telephone set 101 also typically
includes a modular RJ11C plug 113 which couple to
eorresponding modular RJ11 C receptacl~ 114 in cellular
telephone 1 00.
Ceilular telephone 100 includes a cellular telephone
30 transceiver 109 with a radio transceiver 119 and
microcomputer 129 with memory therein for controlling
the operation thereof. Cellular telaphon~ transceiver 1û9
may ba any conventional cellular telephona transceiver
having a radio transmitter, radio reeaiv~r and logic unit,
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such as, for axample, the transceiver shown and described
in Motorola instruction manual number 68P81 066E40,
entitled "DYNATAC Csllular Mobile T~l~phone 800 MHZ
Transceiver," published by and availabl~ from Motorola C &
5 E Parts, 1313 East Algonquin Read, Sehaumburg, Illinois
601 96.
Cellular telephone 100 also includes blocks 102-106
for interfacing cellular telephone transceiver 109 to
telephone set 101. Blocks 102-107 provide the audio,
10 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 intslligent RJ11C Intsrface,~ published by
15 and available from Motorola C & E Parts, 1313 East
Algonquin Road, Schaumburg, Illinois 60196.
Voltage generator 107 gen0rates a 48V DC voltage
which is coupled to wires 112 for supplying approximately
twenty milliamps of current to operats telephone set 101.
20 P~ing voltage gensrator 108 produces a ringing sigrial having
a high voltage at a rate comrnonly used in talephone
systems and being coupled via volta~e generator 107 to
telephone s~t 101. Ths rate of the ringing signal produced
by ring voltage gensrator 106 is controlled by
25 microcomputer 108 via control signal 118.
Audio circuit 102 is an electronic bridge circuitry
which converts the two-wire balanc~d audio from telephone
set 101 to four-wire unbalanced audio iØ, transmit and
receive audio needed in a duplex telephone system. The
30 four-wire unbalanced audio from audiu circuit 102 is
coupied to the radio receiver and radio transmitter of radio
transceiver 119. The transmit audio from audio circuit 102
is also coupied to DTMF detector 104.
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Hookswitch detector 103 detects the transition of
telephone set 101 from "on hook~ to ~off hook~ or vice versa
and produces a hookswitch signal 117 having a binary zero
state when telephone set 101 is on hook and a binary one
stat~ when t~l~phone s~t 101 is off hook. During pulse
dialing, the hookswitch signal 1 17 from d~tector 103
transitions from tha binary on~ stats to the binary zero
state for each dial pulse. Hookswitch signal 117 from
detector 103 is coupled to microcomputer 108 and dial tone
10 generator 105. Microcomputer 108 monitors the
hookswitch signal 117 from detector 103 to determins
wh~n tslephone set 1û1 is eff or on hook and to detect the
digits of a pulse dialed telephone number.
Dial tone ganerator 105 is responsive to control
15 signal 115 from microcomputsr 108 and the hookswitch
signal 117 from detector 103 for generatin~ dial tone when
telephone set 101 comes off hook. Dial tone is generated
when the hookswitch signal 117 from detector 103 and
control signal 115 from microcomputer 108 change to a
20 binary one state. Upon detection of dialing, control signal
115 from microcomputer 108 changes from a binary one
state'to a binary zero state to shut off dial tono generator
105. In other embodim~nts, dial tone may ~be internally
generated in micracomputer 108 and coupled to audio
25 circuit 102 for application ~o telephone set 101.
DTMF detector 104 is coupled to the transmit audio
from audio circuit 102 for det~cting ton~ dialed digits of a
dialed telephonc number. Detector 104 may be a
oommerciaily available detector which translates dual-
30 tona multi-frequency (DtMF) tones into a four-bit binary
equivalent which is coupl~d to microcomputer 108 for ~
processing. To select behNeen tone or pulse dialed digits,
an input signal to microcomput2r 108 may be coupled to a
binary zero or binary one by a jumper wire or a user-
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programmable switch depending on the type of telephone
set 101 coupled to cellular telephone 100.
Microcomputer 108 with mernory therein controls
blocks 105 and 106 and is responsive to hookswitch signal
117 and digits dialed from telephone set 101 for answering
and placing collular t~lephone calls. On r~c~ipt of an
incoming call, microcomputer 108 enables ring vol~age
generator 106 for ringiny telephon~ set 101. If a call is
initiated by telephone set 101 coming off hook,
10 microcomputer 108 decodes the following pulse or tone
dialed digits and, according to the present invention,
forwards each digit on a real time basis to the
microcomputer 129 of cellular telephone transcaiver 109.
Each dialed digit is stored by microcomputer 129. When
15 microcomputer 129 detects the absence of dialed digits for
a predetermined tim~, a cellular telephone phone call is
automatically placed. Thus, by utilizin~ the present
invention, th~re is no need to det~ct a specific number of
digits (e.g. ssven digits in local numbers and ten digits in
20 long distancs numbers) and no need to generata a "SEND~
signal as was done in the prior art. As a result, cellular
telephone 100 accommodates any dialing pattern regardless
of the number of digits of the telephone number.
In the preferred embodiment, microcomputer 108 is
25 coupled to microcomputer 129 of cellular telephone
transceiver 109 by way of a thr~e-wire data bus 111,
which is illustra~ed and described in US Patent No.
4,369,516. Microcomputer 108 is essentiaily continuously
looking for dialed digits and forwarding aach digit on a real
30 time basis to microcomputer 129. Each digit detected by
microcomputer 108 is coded into a message and
transmitted via bus 111 to microcomputer 129.
Microcomputer 129 receives each dialed digit from bus 111
and stores the received digits in a pre-selected location of
WO 90/1477:9 ~ ' PCI'/US90/01797
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i; memory. If another di~it is not received in a
predetermined time (fiv~ seconds in the preferred
embodiment), the digits stored in the pre-selected memory
location of microcomputer 129 ar~ transmitted via the
cellular radio channels by the rablio transmitter of radio
transceiver 119 for initiating a c~311ular telephone call.
Refarring next to Figure 2, there is illustrated a flow
chart for the process used by microcomputer 108 in Figure
1 for processing dialed digits of a telephone number.
10 Entering at START block 202, the process proceeds to
decision block 204, where a check of the hookswitch signal
117 is mad~ to datermine if telsphone set 101 is off hook.
If not, NO branch is taken to wait. If telephone set 101 is
off hook, YES branch is taken from decision block 204 to
15 block 206, where microcomputer 108 generates a binary
one state of control signal 115 to generate dial tone. ~lock
206 may also be reached via branch A if an invalid
tclephone number has been dialed, as explained hereinbelow
with respect to Figure 4. Next, at block 203, a chack is
20 made to determine if a digit has been dial~. If not, NO
branch is taken to wait. If a digit has beon dialed, YES
branch is taken from decision block 208 to block 210 where
a binar zero state of control signal 115 is genorated and
the dialed digit is coded into a messago and sent via bus
25 111 to microcomplJter 129. Next, at decision block 212, a
check of the hookswitch signal 117 is made to determine if
telephone set 101 is still off hook. If so, YES branch is
taken back to decision block 208 to repeat the foregoing
process. If telephohe set 101 is not off hook, NO branch is
30 taken from decisiorl block 212 to block 214 to return to
other tasks.
Referring next to Figure 3, there is illustrated a flow
chart for the process used by microcomputer 108 in Figure
1 for processing incoming telephone calls. Entering at
WO 90/14729 PCr/US9OtO1797
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START block 302, the process proce~ds to decision block
304, where a check is made to determin~ if an inccming
call has been received. If not, NC) branch is taken to wait.
If an incoming call has been received, YES branch is taken
5 from decision block 304 to block 306, where
microcomputer 1û8 gansratcs a binary one state of control
signal 116 to generate the ringin~ signal. Next, at d~cision
block 308, a check of the hookswitch signal 117 is made to
determinc if telephone set 101 is off hook. If not, NO
10 branch is taken to wait. If telephone set 101 is off hook,
YES branch is taken from decision block 308 to block 310 to
generate a binary zero state of control signal 116, connect
the call and thereafter return to other tasks at block 312.
Refsrring nsxt to Figure 4, there is illustrated a flow
15 chart for the process used by microcomput~r 129 in
cellular telephone transceiver 109 in Figure 1 for receiving
dialed digits of a telephone number and placing a cellular
telephone call to the dialed telephone number. Entcring at
START block 402, the process proceeds to decision block
20 404, where a check is made to determine if a dialed digit
has been rsceived in a messags via bus 111 from
microcomputcr 108. If not, NO branch is taken to wait. If a
dialed digit has been received, YES branch is taken from
decision block 404 to block 40~, where a five-second timer
2~ is reset and started. In the preferred embodiment, a five
second timer implemented by interrupt based soft Nare is
used to measure time elapsed since the last dialed digit
was received. In other embodiments, such timer may be
impl~mented by separate timing circuitry and may have a
3û vaiue which depends on operating charactsristics of
telephone set 101. Next, at block 408, the received digit is
stored in a pre-selected location of the memory of
microcomput~r t29. Then, at d~cision bleck 410, a check is
mad~ to de$armine if another dialed digit has been received.
W O 90/14729 ~! 3 ~ P~r/US90/01797
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If so, YES branch is taken from deoision block 410 back to
biock 406 to repeat the foregoing process. If another dialF~d
digit has not been received, NC) branch is taken from
decision block 410 to decision block 412, where a check is
5 made to determine if the five-second timer has timsd out.
If not, NO branch is taken back to decision block 410 to
check for receipt of ~he next dialeti digit, if any. If the
five-second timer has timed out, YES braneh is takon from
decision block 412 to decision block 418, wher~ the dialed
10 digits are checked to determine if a valid telephone number
has been dialed. For example, the dialed digits are checked
to determine if seven digits ar~ pr~sent for local numbers,
ten digits ar~ present for long distance numbers preceded
by a one or zerot thrae digits are present for 411
15 information, 611 telephone repair and 911 emergency, and
other digit sequences depending on the country and
telephone system in which cellular telephone is being used.
If the dialed digits are not valid, NO branch is taken from
decision block 418 to branch A to rsturn to the flow chart
20 of Figure 2 and generato dial tone again. Thus, according to
a feature cf the present invention, dial tone is returned to
the user of eellular telephone if an invalid telephone
number is dialed. If th~ dialed digits ar~ valid, YES branch
is taken from decision block 418 to block 414 where a
25 cellular telephone call is plaoed to the number comprised of
the digits stored in the pre-selected memory location of
microcomputer 129, and thereafter return to other tasks at
block 41 6.
In summary, a unique csllular telephone automatically
30 places and receives cellular talephone calls dialed in any
pa~srn on a standard pulse or ton~ dial telephone set or
equivalent d~vice. The dialed digits of a telephone number
are processed by the unique c011ular telephone of the
present invention on a real-time basis resulting in
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automatic placement of a cellular telephone call without
using a "SEND" button or circuitry that simulates the "SEND"
function as in the prior art.
