Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2158481
A mobile communication equipment
The object of the present object is a telecommunications equipment
and, more particularly, a pocket telephone which can be taken aboard a
veh icle .
Numerous manufacturers Or worldwide reputation produce and market
all sorts of mobile or portable telephones, which all offer specific
advantages, but of which none can provide a solution to all the situa-
tions of use to which a user is confronted, with all his requirements.
Actually, so-called "portable" telephones are available which are
lightweight, small in size and therefore easily carried, but their au-
tonomy is relatively short and above all they cannot be used when dri-
ving an automobile since one does not know where to affix them in the
car; as mentioned, their autonomy is too short for a prolonged use wi-
thout recharging or changing the batteries and, above all, they are not
equipped with a "hands free" system, i. e. with a spacially diffusing
microphone or a loudspeaker allowing the driver to drive his car during
a telephone conversation without llolding in one hand said portable te-
lephone. Even though this is still tolerated at present, it will soon
not be the case any more, for obvious reasons of safety, since the dri-
ver, who must concentrate on his telephone conversation, cannot at the
same time drive carefully and safely his vehicle if only one hand is
available, the other one being necessarily used for holding the por-
table telephone. The non availability of a "hands free" system is also
a drawback when the equipment is used elsewhere than in a car and when
several persons are to take part in the conversation.
There are also car telephones which are installed permanently in a
2158~81
conventional car and which are generally provided with a "hands free"
system. These apparatuses require a permanent installation in the car
and cannot therefore be used as portable telephones; they are in fact
telephone sets which are permanently attached to a vehicle. These tele-
phones need installation work on the vehicle.
There are further telephone sets of the portable type which can be
used everywhere. They are quite bulky, their autonomy is sufficient,
but they are heavy because of their large-sized batteries, they are
most often not provided with a "hands free" system, so that they cannot
be used for conferences between several persons and their use in cars
is not problem free, since no means are provided for holding them in
place and they can hence fall over during a rough ride, at a bend, etc.
These apparatuses have the size of a small attaché-case and are hence
bulky and heavy, and they are accordingly less and less used, except in
holiday houses or as second permanent telephone sets.
The object of the present invention is a telecommunications system
and, more particularly, a pocket telephone which can be used in cars
and for conferences.
It includes an accessory weighing less than 120 grams which allows
the instant conversion of a pocket radiotelepllone into a "hands free"
car telephone or, when desired and also instantly, the pocket telephone
into a home telephone which is also "hands free" and which can be used
when one's hands are busy or to organize a telephone conference between
two working parties remote from each another.
Several unsuccessful attempts have been made, to try and acljoin a
"hands rree" pocket system to a pocket ra(liotelepllone. These attempts
hRve nll rniled, because n surficient miniaturizntion Or the "hnnds
21S8481
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free" system could not be achieved, accompanied by an elimination of
the Larsen effect thereby created.
The present equipment overcomes the drawbacks of the above-
mentioned apparatuses and is defined by the characteristic features of
claim 1.
The annexed drawing illustrates schematically and by way of example
several possible embodiments of the telephone equipment according to
the invention.
Figure 1 illustrates in a perspective view of a first embodiment of
the telephone equipment and of a pocket telephone.
Figure 2 is a wiring diagram of a portion of the "hands free" cir-
cuit contained in the multiple function connector or in a support.
Figure 3 is a wiring diagram of a portion of the electronic circuit
of the "hands free" device contained in a case or a support.
Figure 4 illustrates in a perspective view a second embodiment of
the telephone equipment according to the invention.
Figure S illustrates a perspective view a third embodiment of the
telephone equipment according to the invention.
Figure 6 is a wiring diagram of the electronic circuit contained in
the support of the third embodiment illustrated in figure 5.
The pocket telecommunications equipment according to the present
invention includes a pocket telephone having an extended autonomy,
owing to a rechargeable battery, and incorporating all the options
available with the high-technology apparatuses of this type. The appa-
ratus can be of the "Natel C" type, "Telecom 2000" or any other, fitted
with its antenna.
The present pocket telephone is particularly well suited for taking
2158481
aboard a vehicle, to be used as a car telephone with the "hands free"
equipment, without at the same time requiring any permanent installa-
tion inside the vehicle. It is also particularly well suited for use in
conferences involving several persons, also without requiring any per-
manent installation.
In the first embodiment illustrated in figures 1 through 3, this
pocket telephone 1 is connected mecllanically and electrically by means
of a multiple function connector 5 ancl a single cable 2 to a "hands
free" case 3 and to a low-voltage power supply plug 4, generally of the
"cigarette lighter" type.
The body of the "hands free" device can have, in particular, the
shape of a small case of approximately 4 cm x 4 cm x 2 cm, it includes
an electronic printed circuit adapted to the electronics of the pocket
radiotelephone. This circuit manages and distributes the signals accor-
ding to a predetermined scheme, between the different elements of the
telephone, of which the power supply levels range from 7 to 30 V. In
the other possible versions, there is provided inside or outside this
housing an audio diffuser system which makes it possible to hear clear-
ly the partner, when the telephone set is at a short distance and vi-
sible to the user.
The electric cable 2 has electric conductors ensuring the connec-
tion between the "cigarette lighter" plug and the pocket telephone 1,
to ensure both is power supply and the charging of its incorporated
battery .
Finally, this electric cable 2 provides at the same time the mecha-
nical support of the "hands free" case 3. To this end, this "hands
free" case 3 is located in the vicinity of the "cigarette lighter" plug
2158481
s
4 and the electric cable 2 or at least its sheathing in the section
connecting this plug 4 to the "hands free" case is mechanically resis-
tant and relatively rigid. Accordingly, when the plug 4 is engaged in-
side the "cigarette lighter" jack of a vehicle, this section of the ri-
gid cable acts as a support and as a fastening means for the "hands
free" case.
Conversely, tlle other portion of cable 2 connecting the "hands
free" case to the pocket telephone is flexible and extensible, as it is
the common practice, to provide for ease of handling of the pocket te-
lephone 1.
The end of the cable 2 is connected to the pocket telephone I by
means of a connector 5. This connector carries a part of the "hands
free" electric circuit of the present equipment, illustrated in figure
2 and includes in particular a microphone 6 and its associated circuit.
When the connector 5 is connected to a pocket telephone set 1, the mi-
crophone 6 is automatically switched on, wlllle that incorporated into
the telephone set is automatically switched off.
This connector 5 can be plugged in by means of its connexion pins
a...g into the pocket telephone 1 and is connected by the multiple-wire
cable 2b to the case 3. The switch S makes it possible to actuate ei-
ther an external antenna or the internal antenna of the device.
The pocket telephone is furthermore provided with a fastening mem-
ber for mounting on the surface of the dashboard of a vehicle or for
placing it on a seat so that it cannot move. This fastening member can
be made as a suction cup affixed to the pocket telephone, which makes
possible its attachment to a smooth surface by the simple exertion of a
pressure.
2158~81
-- 6 --
This fastening member can also be formed as a strip of fabric bea-
ring hooks, affixed to the pocket telephone 1 and cooperating with a
corresponding strip of fabric bearing hooks affixed to where the user
wishes. This second strip of fabric bearing hooks can be affixed for
example to a heavy pad, for example loaded with small shot, which has
one non-slipping surface. One can thus fasten the pocket telephone
anywhere or lay the pad down and apply the telephone set thereto.
The assembly formed by the pocket telephone and its power supply
cable carrying the connector, the "hands free" case and the "cigarette
lighter" plug needs very little space. It can be stored away in a very
small bag. This would remain true even if the user wanted to take with
him a device for charging and power supplying through the electric net-
work and a member for affixing the telephone, i.e. a suction cup or
pad .
A universal pocket telephone is thus obtained which is of a very
small bulk.
Thus, this equipment, which is primarily designed for use in vehi-
cles without having to be mounted fixedly, can also be used as a pocket
telephone outskle the vehicle.
This equipment is designed to include a 220 V / 12 V transformer-
rectifier provided with an electric cord for connection to a 220 V
electric network and a jack identical to that of the cigarette lighter
of the car.
Thus, the user can power supply his pocket telephone 1 and recharge
its battery elsewhere than in his car, by using the power supply case
and such a transformer. One can hence use this pocket telephone as a
telephone with spacially diffusing loudspeakers for conferences invol-
2158481
ving several users. One can thus use this telephone as a "hands free"telephone with spacially diffusing loudspeakers both inside a car and
in a conference room or at home.
Accordingly, this apparatus satisfies all the requirements placed
both on a car telephone and on a pocket telephone with spacially diffu-
sing loudspeakers, without having any of the drawbacks of existing ap-
paratuses.
This is achieved, in particular, by the physical separation of the
HP loudspeaker from the "hands free" case 3 and the microphone 6 of the
connector 5 and their associated anti-Larsen circuits, replacing the
microphone and the loudspeaker of the telephone 1 itself, when it is
connected to the present equipment.
It can be used both as a car telephone set or as a pocket tele-
phone, without requiring any particular installation for any of its
uses. The device, which weighs only 120 grams is infinitely lighter and
of course much less bulky than a mobile telephone, while retaining all
its capacities and ease Or use. When tlle pocket telephone is removed
from the above-mentioned "hands free" device, it has again its initial
weigh, while retaining the totality of its functions and all its mobi-
lity as a pocket telephone; in a car, it requires no fixed installation
in the vehicle, has a "hands free" system and special anti-Larsen cir-
cuits, and is provided with holding or fastening means which are simple
and novel, for example a suction cup or a pad. Furthermore, it can be
power supplied from the "cigarette lighter" jack of a vehicle, which at
the same time ensures the charging of the battery, so that the total
capacity of the rechargeable battery of the pocket telephone is always
available when the latter is used separately. When used in a conference
2l58181
room, it can be connected to a 220 V electric network via an auxiliary
transformer.
For the individual user, this equipment furthermore offers the ad-
vantage that it can be used in any store, shop, supermarket, etc, since
it requires no mounting and is instantly ready to be used as soon as a
dial number is affected thereto by the appropriate administration,
which could even be done in the future at the point of time when the
item is purchased.
In the case of companies leasing cars and managing fleets of seve-
ral thousand cars, this apparatus could be even more advantageous.
There is no point in such companies equipping all their cars with the
"hands free" system or even with telephones, which means that a custo-
mer can only rent at a high cost a luxury car equipped with a tele-
phone, provided one is still available.
With the equipment proposed in this invention (pocket radiotele-
phone ~ pocket "hands free" device), this equipment can be rented inde-
pendently of the rental of the car and placed into the luxury car or
into the standard car selected by the customer.
1. A complete "hands free" telephone system can be connected to the
"cigarette lighter" jack of the car, and provide access immediately
to the world telephone system, simply and neatly, without any ins-
tallation cost, nor the purchase of any additional item.
2. The user can change to another car, immediately and without the as-
sistance of a technician, and continue to use his telephone in atotally reliable manner in another car, or in any other place out-
side h is car .
3. Should the user decide to go walking or go travelling by train,
2158~81
taxi or ship, he will take with him his pocket telephone, possibly
with an additional battery in his luggage and a small conventional
power supply plug for recharging the batteries from time to time.
4. The options and freedom offered by a car leasing company to their
customers will be considerably increased, since the latter will
have the possibility of choosing any car from the fleet and never-
theless enjoy the benefits of a portable telephone, without the
need that all the cars be equipped with any permanent installation.
For a car leasing company, this advantage would represent savings
of about 80% of the cost of installing a conventional "hands free"
standard system, i. e. mounted fixedly, in each vehicle.
5. The user can also connect the pocket telephone to the 220 V elec-
tric network via an auxiliary transformer and have at his disposal
a telephone with spacially diffusing loudspeakers in any office or
prem ises .
In the embodiment illustrated in figures 1 through 3, the assembly
forming the portable telecommunications system consists of a pocket te-
lephone 1 and of a low-voltage power supply/"hands free" device.
This low-voltage power supply/"hands free" device includes a
"cigarette lighter" plug 4 designed for plugging into a low-voltage po-
wer supply jack, a "hands free device" 3 and an electric cable 2
connecting on the one hand the pocket telephone 1 to the "hands free"
case 3 via a multiple function connector 5 incorporating the "hands
free" microphone and its associated circuit and, on the other hand,
this "hands free" case 3 to a low-voltnge power sllpply plu~ ~. Tllis
clectric cablc inclll(les n first portion 2n WhiCIl iS relntively rigill
nn(l sllort bctwccn Ihc phlg ~i nn(l the "hnn(ls rrce" cnsc 3, nn(l n sccon(l
215~481
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portion 2b which is flexible, extensible and relatively long, between
the "hands free" device 3 and the connector 5.
This assembly allows the user of a pocket radiotelephone to
converse without having to place the handset against his ear. The user
can leave the handset on its support, provided the same are in full
view of the user.
This has been made possible by the use of a sophisticated electro-
nic circuit including several high quality filters and various low-
noise amplifier circuits, all connected to a special loudspeaker and a
special microphone, housed respectively in the case 3 and in the
connector 5. Even though the circuit was miniaturized, the device could
be made without any trace of the Larsen effect, to produce a communica-
tion which is 100~ neat and clear, in a duplex communication.
Figure 2 illustrates this electronic circuit housed in the case 3,
which includes two amplifier stages using the integrated amplifiers U1
and U2 of the 082 type, wherein the BFIN input receives the low-
frequency signals arriving from the pocket telephone 1. The output of
this chain of amplifiers is fed via an adjustable potentiometer Pl to a
filtering circuit including in particular an integrated circuit U3 of
the MC 34019 type supplying the loudspeaker HP. This electronic circuit
makes it possible to avoid ancJ to suppress any oscillations parasites
or interrercnces between tl1e loudspeaker l-IP nnd the micropllone incorpo-
rntc(l inlo the conllcclor 5.
I;urthermore, a low-voltage power supply is incorporated so that it
can also power supply the pocket telephone when it is connected to the
"hands free" device, which makes it possible to decrease the number of
connections necessary for the use of a multiple function connector 5
11 21~8481
between the portion 2a Or the electric cable 2 and the pocket telephone
1. This supply allows for the simultaneous power supply of the electro-
nic circuit of the "hands free" device and the recharging of the batte-
ries of the pocket radiotelephone 1, so that the same may be constantly
ready for use without an external power supply.
This low-voltage power supply is connected to the "cigarette ligh-
ter" plug by two leads V BAT IN and is grounded, and it produces a
first voltage ~V for power supplying the pocket telephone and the inte-
grated circuit U3, as well as a second voltage ~V/2 for power supplying
the "hands free" electronic circuit.
Clearly, this embodiment makes it possible, to limit the number of
electric conductors in cable 2 to two conductors in the portion 2a and
to three in the portion 2b of the cable 2.
The assembly of the "hands free" electronic circuit, of the power
supply and of the loudspeaker are housed in a small rigid case.
In the example illustrated, a multiple function connector 5 allows
the connection of the power supply/"hands free" device 2, 3, 4 to the
pocket telephone 1 and incorporates the microphone and its associated
circuit.
In brief, the "hands free" equipment proposed includes:
a) A molded connector which fits snugly into a mobile cellular tele-
phone. It includes an anti-Larsen circuit, a preamplifier and filters.
There is also incorporated a microphone, held in an injected silicone
membrane specially designed for preventing the transmission of vibra-
tion, which, without such a means, would produce a background noise
when sounds are emitted.
b) A compact moulded box incorporating a "system management" printed
2158981
circuit, a "fast recharge" circuit (from O to 90% in 1 hr), a loudspea-
ker with its amplifier and a potentiometer adjustable by means of a
small serrated wheel protruding by 2 mm on one side of the box.
c) A car "cigarette lighter" phlg.
d) A light spirally shaped cable which extends from part S through part
3 and ends at part 4.
Figure 4 illustrates a second embodiment Or the telecommunications
equipment according to the invention. Tn this embodiment, which is even
more compact and easy to use than the first one, the mobile telephone
or pocket telephone 1 can be placed on a support 10 which can be atta-
ched to any component of the dashboard of a vehicle, for example by a
selfadhesive strip or a strip of a fabric bearing hooks. This support
10 includes, in its lower part, a connector which corresponds to that
of a radiotelephone and which can be plugged for its operation, i.e.
its power supply and the recharging of its own batteries, into the ci-
garette lighter jack of a vehicle. The lower part of this support 10
includes, in the same way as the connector 5 of the first embodiment, a
microphone 11 which, upon the placement of the radiotelephone on the
support is automatically switched on, whereas that incorporated into
the pocket telephone is switched off.
The lower part of the support 10 includes the loudspeaker 12,
which, in the first embodiment, was placed inside the case 3.
Electronic charging circuits and anti-Larsen circuits similar to
those illustrated in figures 2 and 3 are included in this embodiment,
molded or embedded in the body forming the support 10.
The spirally shaped cord 13 connects the support, its electronic
circuits, the connector, the microphone 11 and the loudspeaker to the
2158481
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plug 14 of a cigarette lighter.
This second embodiment is even more convenient to the user, since
the support 10 can be fastened removably or not, inside a vehicle, and
connected to the cigarette lighter: the user only needs to place his
pocket telephone on the support when he climbs into his car.
Thus, in this second embodiment which is more compact and easy to
use, the equipment includes in particular a microphone, an anti-Larsen
circuit, an amplifier and a fast charger for the battery (from 0 to 90~
in 1 hr) housed in a support. This system makes it possible to bring in
an appropriate vicinity the loudspeaker ànd the microphone, which fur-
ther facilitates the miniaturization Or the system, while avoiding any
Larsen effect. The molded support made integrally contains the system
and measures at the most 15 x 6,5 cm x 4 cm and, depending on the mo-
del, can even be further reduced in size. It will be connected to the
cigarette lighter by means of a continuous spirally shaped cord. Its
total weight is of about 200 g (with the spirally shaped cord and its
connector connecting it to the cigarette lighter of the car). In each
one of the different versions, the equipment is perfectly compatible
with the most recent mobile/pocket telephone sets.
This equipment eliminates all undesirable noises, Larsen effect,
whistling sounds, buzzing and other background noises, it transmits and
reproduces simply, accurately and with the same degree of quality, all
the sounds which are received or emitted through the cellular telephone
network to which it is connected.
The third embodiment illustrated in figures 5 and 6 of the telecom-
munications equipment, which is the most sophisticated embodiment and
which is also the preferred design, includes a mobile telephone 20
21S8481
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which can be placed on a support 21, connected by an extensible lead 22
to a plug 23, here the plug of a cigarette lighter, making it possible
to connect it electrically to a source of electric energy either direc-
tly, in the case of the cigarette lighter of a vehicle being used, or
via a transformer in the case of a connection to an electric network.
The support 21 can include means for fastening the same to the
dashboard of a vehicle or a conference table. It includes conventional
electric connections or contacts, cooperating with those of the mobile
telephone 20, which can be plugged into the mobile telephone, to pro-
vide for the functions of charging the battery of the mobile telephone
20 and switching off of the incorporated loudspeaker and the micro-
phone, which are replaced by a loudspeaker 24 and two microphones 25,
26 mounted in said support 21, when the mobile telephone 20 is placed
on the support 21.
The geometrical and/or spatial positioning of the microphones 25,
26 with respect to the loudspeaker 24 is critical. A symmetrical arran-
gement is essential to ensure a transmission of the audio signals of
the loudspeaker 24 to each microphone with an intensity substantially
identical .
The microphones 25, 26 are furthermore positioned or designed in
such a manner as to receive the sounds from their surrounding in a di-
rectional or selective manner, the microphone 25 being mucll more sensi-
tive to sollnds coming from the lert of the support, whereas the micro-
r)hone 26 is mllCIl morc sensitive to the sol~n(ls coming from the right
hnnd sidc Or the slll-port 2l.
Tl~c clcctrollic circuit Or this thircl em(~odimellt is illustrntecl
schelnatically in figure 6.
2158481
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The two microphones 25, 26 are connected to the terminals Ml~, M1-
and M2~, M2-, whereas the terminals FL3, FL4, FL6, Bat~ and Bat- are
connected to the support contacts 21 designed for cooperating with the
contacts of the mobile telephone 20, when the same is placed on the
support 21.
One can see that the signals of the microphones 25, 26 are fed to
the inputs of a differential amplifier IC4A; LM833N, of which the out-
put signal corresponds to the difference in the signals output by the
microphones 25, 26.
Thus, when these microphones 25, 26 are stressed by the loudspeaker
24, their output signals substantially cancel each other since they are
positioned symmetrically with respect to this loudspeaker 24. However,
when they deliver signals originating from the user of the telephone,
who is never centrally positioned with respect to the support 21, the
difference between the signals of the microphones 25, 26 produces a si-
gnal of a sufficient value for the functioning of the telephone
equipment.
Thus, through the symmetrical disposition of the two microphones
with respect to the loudspeaker and the use of a differential ampli-
fier, substantially all the problems of oscillations parasites and
Larsen effect are eliminated in a manner which is simple, intelligent
and effective.
The functioning of this third embodiment is as follows:
Upon insertion of the mobile telephone 20 in the support 21, a
switch designed for this purpose causes the switching on of the louds-
peaker 24 and of the external microphones 25, 26. A fast charger is al-
so switched on and allows the charging of the battery included in the
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mobile telephone, if necessary. Circuits which form part of the elec-
tronics of the system adjust the voltages necessary for the proper
functioning of said electronics. To facilitate the description Or the
device, one should consider the three principal parts:
1. Receiver circuit of the partner:
The signal produced by the mobile telephone 20 corresponding to the
message being received is brought through appropriate connections to
the circuit IC5, which is an important component. The main function of
this component is to prevent that the loop, including the microphones
of the device, the transmission circuit of tlle signals of the user, the
receiver circuit of the partner as well as his loudspeaker, followed by
the microphone of this same partner and all the circuits up to the
loudspeaker of the user of the device, starts oscillating (oscillations
parasites or Larsen effect) when the overall gain of the loop described
reaches a sufficient value. After processing and after an amplification
carried out by the circuit IC3, this signal is used for actuating the
loudspeaker HP, which will produce an audio output which is adequate
for the intended purpose.
2. Circuit for processing signals:
To describe the functioning of this circuit, one must consider that
the device can be, at any given time, in one of the three following
states:
a) transmission (the user is talking)
2158481
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b) reception (the partner is talking)
c) standby (neither the partner, nor the user is speaking)
To each one of these states will correspond certain internal condi-
tions in the processing circuit. To simplify, the amplification of the
microphones will be maximum during the state of transmission; to this
maximum gain of the microphones will correspond a minimum amplification
of the loudspeaker for the corresponding signal. In the same manner,
when the device is in the reception state, the amplification of the si-
gnal of the partner will be maximum at this loudspeaker and to this
maximum gain at the loudspeaker will corlespond a minimum amplification
of the signal of the microphones of the user. In the standby state, in-
termediate amplification levels are defined, again for the purpose of
preventing oscillations parasites or the Larsen effect.
The use of two microphones mounted symmetrically with respect to
the loudspeaker, as well as with respect to the front face of the de-
vice, provides several advantages in this mode of utilisation:
1) The acoustic signals transmitted by the loudspeaker will be re-
ceived in a manner substantially identical by each microphone. A diffe-
rential preamplifier makes it possible to attenuate, if not to elimi-
nate, the common component arriving from the loudspeaker, which results
in a significant decrease of the signal which would have produced
amongst others, oscillations parasites.
2) A certain attenuation of the ambient noise is equally obtained
in this manner.
2158181
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3) Owing to the position of microphones, the utilization
by the front seat passengers will be perfect.
4) The equipment can be used indifferently in a vehicle with a
steering wheel on the right hand side or on the left hand side, without
any modification.
