CA2019166A1 - Telephone apparatus adapted to be connected to several telephone lines - Google Patents
Telephone apparatus adapted to be connected to several telephone linesInfo
- Publication number
- CA2019166A1 CA2019166A1 CA002019166A CA2019166A CA2019166A1 CA 2019166 A1 CA2019166 A1 CA 2019166A1 CA 002019166 A CA002019166 A CA 002019166A CA 2019166 A CA2019166 A CA 2019166A CA 2019166 A1 CA2019166 A1 CA 2019166A1
- Authority
- CA
- Canada
- Prior art keywords
- circuit
- line
- handset
- call
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/002—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems
- H04M9/005—Arrangements for interconnection not involving centralised switching with subscriber controlled access to a line, i.e. key telephone systems with subscriber controlled access to an exchange line
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/71—Substation extension arrangements
- H04M1/715—Substation extension arrangements using two or more extensions per line
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/02—Arrangements for interconnection not involving centralised switching involving a common line for all parties
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Interconnected Communication Systems, Intercoms, And Interphones (AREA)
- Prepayment Telephone Systems (AREA)
- Telephonic Communication Services (AREA)
Abstract
A TELEPHONE APPARATUS ADAPTED TO BE CONNECTED
TO SEVERAL TELEPHONE LINES
ABSTRACT OF THE DISCLOSURE
The apparatus, able to be connected to any one of several telephone lines, saves the user from having to manually select a free line when he wants to make a call. To this end, the apparatus includes a line voltage detector that produces an engaged signal if, when the user picks up a handset to make a call, the line to which the apparatus is connected is engaged by a call with another telephone connected to the same line. A
control circuit of the apparatus makes use of this engaged signal to connect the apparatus to another line.
TO SEVERAL TELEPHONE LINES
ABSTRACT OF THE DISCLOSURE
The apparatus, able to be connected to any one of several telephone lines, saves the user from having to manually select a free line when he wants to make a call. To this end, the apparatus includes a line voltage detector that produces an engaged signal if, when the user picks up a handset to make a call, the line to which the apparatus is connected is engaged by a call with another telephone connected to the same line. A
control circuit of the apparatus makes use of this engaged signal to connect the apparatus to another line.
Description
1 6 ~
Backaround of the Tnvention The present invention concerns a telephone apparatus adapted to be connected to a plurality of telephone lines each able to have a free state and an engaged state and S each able to transmit a call signal, including an electro-acoustic unit comprising a microphone and an earphone and switching means responsive to any one of said call signals to selectively connect said electro-acoustic unit to the line that transmits this call signal.
Such apparatus are well known. Thus, for example, the I Swiss telephone administration offers for rental to its ¦ subscribers an accessory called "Accessory for two lines Tritel BZ 85.22" that can be connected to two telephone lines and to a conventional telephone set to form with it an apparatus corresponding to the definition given above.
When a call signal is received on one of the two lines connected to the apparatus, the above-mentioned accessory automatically sets up a connection between this line and the telephone set so that when the set's user lifts up the handset to reply to the call, he is ; immediately connected to the caller without having to make any further manipulation.
If one of the two lines has been designated as a priority line and the above-mentioned accessory has been set accordingly, the handset of the telephone, on being picked up by the user to make a call, will always be connected to this priority line.
Otherwise, to make a call, the user must select one of the two lines by actuating a push button.
It is more and more frequent for two or more telephone sets to be connected in parallel on the same subscriber's line, these different sets being for example situated in different rooms of the same appartment or house.
In such a case, the chances are that when the user of an apparatus such as that described above picks up his ..
, :
:-' 2~9~ ~6 telephone handset to make a call, the handset is connected to a line that is already engaged by another call. This user must then manually select the other line to be able to make his call.
Summ~ry of the Tnvention An object o~ the invention is to propose a telephone apparatus of the above-defined kind but which does not have this drawback, i.e. whose handset is automatically connected to a free line, if there is one, when the user picks it up to make a call.
This object is achieved by the claimed apparatus.
Brief nescri~tion of the Drawinas The invention will now be described with reference to the accompanying drawings in which:
- Figure 1 schematically shows a first embodiment of the apparatus according to the invention ;
- Figure 2 is the block diagram of a control circuit that can be used in the apparatus of Figure 1 ;
! - Figure 3 is the block diagram of a line voltage ~20 detector that can be used in the circuit of Figure 2 ; and I- Figure 4 schematically shows a second embodiment of the apparatus according to the invention ~etailed Descrip~ion The telephone apparatus according to the invention shown schematically in Figure 1 by reference 1 comprises four connection terminals la, lb, lc and ld. Terminals la and lb are adapted to be connected to two wires A1 and A2 that together form a telephone line A connected at its other end to a telephone exchange. Terminals lc and ld of the apparatus 1 are connected to two wires B1 and B2 together forming a second telephone line, B, also connected at its other end to a telephone exchange.
The apparatus 1 further comprises, as is conventional, a base (not shown) connected by a cord to a handset 2 comprising an earphone 3 and a microphone 4.
~, ,~....................................... : .
::!:' ,' ' . ,, , `
~.i" ~
,' ~: ',,, ' . ` , .i,.~ ,, ~ :, . j 2~g~
When the handset is not being used, it can be placed on a ¦ support incorporated in the base.
As is also conventional, the handset 4 is connected to the output of a speech circuit 5 by means of which the signals adapted to energize the earphone 3 can be separated from those produced by the microphone 4.
The apparatus 1 also includes a bistable relay 6 comprising two coils 6a and 6b each having a f irst terminal connected to the positive pole of a power supply that will be described below and a second terminal connected to a control circuit that will also be described below.
The relay 6 also comprises four unipolar contacts 6.1, 6.2, 6.3 and 6.4 mechanically connected together in such a manner that the contacts 6.1 and 6.2 are always in the same closed or open state, and the contacts 6.3 and 6.4 are always in the opposite state to contacts 6.1 and 6.2.
The relay 6 is furthermore arranged in such a manner that the contacts 6.1 to 6.4 are placed in the state illustrated in Figure 1 by a current pulse delivered to its coil 6a, and in their opposite state by a current pulse delivered to its coil 6b. These two states will ~-arbitrarily be designated as being tne first and second 25 states of relay 6. -The first terminals of contacts 6.1 and 6.2 are respectively connected to the terminals la and lb of the apparatus 1, and to the terminals 7a and 7b of a call circuit 7. -~
This call circuit 7 will not be described in detail here because it is well known. Suffice it to say that, in this example, this circuit is arranged in such a manner that its output 7c produces a logic signal that goes high in response to call signals on the line A and goes low in the absence of these call signals. These high and low logic states will be defined below.
`;
., `
~ 2 ~
Also, the call circuit 7 comprises, in conventional manner, a bell, a vibrator or any other similar device able to produce a characteristic sound or noise in response to the above-mentioned call signals. If required, the circuit 7 may also include a signal lamp that lights up in response to these call signals.
Likewise, the first terminals of contacts 6.3 and 6.4 are respectively connected to the terminals lc and ld of the apparatus 1 and to the terminals 8a and 8b of another call circuit 8.
This circuit 8 is similar to the above-mentioned circuit 7. Like the latter, it comprises an output 8c that produces a logic signal that goes high in response to call signals on line B and goes low in the absence of these lS call signals. Like circuit 7, the circuit 8 also comprises a bell, a vibrator or another similar device able to produce a characteristic sound or noise in response to call signals on line B and, if required, a signal lamp that lights up in response to these call signals.
The second terminal~ of contacts 6.1 and 6.3 are connected together to the first terminal of a contact 9.1 which, in the present example, is actuated by a push rod arranged in the support of handset 2 in such a manner that contact 9.1 is open when the handset 2 is not being used and is at rest on this suppor~, and is open when the handset 2 is lifted off the support with a view to being used.
The second terminal of contact 9.1 is connected to the emitter of a bipolar pnp transistor 10 whose collector is connected to a first terminal Sa of speech circuit 5, and to a first terminal lla of a voltage detector circuit 11 that will be described in detail later.
The second terminals of contacts 6.2 and 6.9 are connected together to a second terminal 5b of speech circuit 5 and to a second terminal llb of the voltage detector circuit 11.
~ 6 - 2 ~
The apparatus 1 of Figure 1 further includes a selection pulsesgenerating-circuit 12 that may for example comprise a keyboard having ten keys numbered 0 to 9 and an electronic circuit whose output constitutes the output 12a of circuit 12 and which is arranged so that this output 12a is normally low and supplies, in response to each actuation of one of the keys, a given number of pulses during which it goes high, the number of pulses corresponding to the number of the actuated key.
The apparatus 1 of Figure l also comprises a control circuit 13, an example of which will be described below.
Circuit 13 has inputs 13a to 13d connected respectively to the outputs 7c, 8c, llc and 12a of circuits 7, 8, 11 and 12, as well as an input 13e connected to a first terminal of a contact 9.2 whose second terminal is connected to the positive pole of the above-mentioned power supply. Like the contact 9.1 to which it is mechanically connected, contact 9.2 is open when the handset 2 is placed on the support of apparatus 1 and is closed when this handset 2 is in use.
The control circuit 13 also has outputs 13f, 13g and 13h respectively connected to the second terminals of relay coils 6a and 6b and to the base of the transistor 10 .
The electrical energy required for operation of the various circuits of the apparatus 1 is supplied by either of the lines A and B via a source lq that may, for example, be a simple voltage stabilizing circuit. The inputs 14a and 19b of this source 14 are respectively connected to the second terminals of contacts 6.1 and 6.3 and to the second terminals of contacts 6.2 and 6.4, so as to be connected to either of lines A and B irrespective of the state of the relay 6.
The outputs 19c and 14d of source 14, which respectively constitute its negative terminal, designated by the sign -, and its positive terminal, designated by ,~ 2~9~
the sign +, are connected to the various circuits of apparatus 1 by connections that have not been shown.
Furthermore, negative terminal 14c is connected to the input terminal 14b and its potential is the reference potential for the entire apparatus 1.
The previously mentioned low and high logic states that will be discussed again below correspond respectively to the potential of the negative terminal 14c and to the potential of the positive terminal 14d of source 14.
Figure l also shows that two further telephones are also connected the one to line A and the other to line B. These two further telephones, designated by lS
and 16, can be of any type and will not be described here.
Figure 2 is the block diagram of an example of the control circuit 13 of Figure 1. This circuit 13 comprises AND gates 21 to 26, OR gates 27 to 29, inverters 30 to 34, RS flip-flops 36 to 38, monostable circuits39 and 40, a delay circuit 41, two inverter amplifiers 42 and 43, an npn bipolar transistor 44, and two resistors 45 and 46.
All of these elements are connected to one another and to the inputs and outputs of circuit 13 that are designated by the same references as in Fig. 1, in the manner shown in Fig. 2. In order not to lengthen unnecessarily the present description, these connections will not be described in detail.
Fig. 3 is a block diagram of an example of the voltage detector circuit of Fig. l.
In this example, this circuit includes two resistors S1 and 52 connected in series between terminals lla and llb. The point of junction of resistors S1 and 52 is connected to the base of an npn bipolar transistor 53 whose emitter is also connected to terminal llb and whose collector is connected to output llc and, via a resistor 54, to the positive terminal of the power supply 14.
:,~.. . . -,; . :................................... .
~",""~. :
j., .. ,,, ~ . . . :
- 8 - 2~
The resistors S1, 52 and 54 are selected in such a manner that transistor 53 is conductive, and hence its output llc is low, when the voltage across the terminals lla and llb is equal to the voltage across the two wires of a telephone line when the latteris free, i.e. for instance about 48 volts, and in such a manner that output llc is high when the voltage across terminals lla and llb is equal to the voltage across the two wires of a telephone line when thelatteris engaged, i.e. for instance about 10 volts.
To understand the operation of the apparatus 1 of Fig. 1, about to be described below in conjunction with the operation of the control circuit 13 of Fig. 2, it should be noted tha L ~ in conventional manner, the Q or lS direct output of each flip-flop 36 to 38 is low or high according to whether a high logic signal is applied to its R input or to its S input, the Q or inverted output of each of flip-flop 36 to 38 being obviously always in the opposite logic state to its Q output.
Is should further be noted that each of the monostable circuits 39 and 40 delivers at its output a pulse of given duration in response to each transition of its input from low to high, i.e. this output is high during the given duration and then reverts to low.
As will be apparent from the following description, this given duration is the duration that the current pulses applied to the coil 6a or coil 6b of the relay 6 must have to switch the relay to its first or to its second state, respectively.
It should further be noted that, again in a conventional way, the output of the delay circuit 41 normally has the same logic state as its input, but that, when its input goes from low to high, the corresponding change of its output takes place only after a given lapse of time.
. ~ 2~
.. g To begin with, it will be assumed that the apparatus 1 is not in use, i.e. that the handset 2 is placed on its support and contacts 9.1 and 9.2 are open, and that telephones 15 and 16 are also not in use.
In these conditions, the input 13a of circuit 13 is kept low because it is connected to the negative terminal of the current supply 14 via resistor 45.
Also, in the same conditions, the other inputs 13a to 13d of circuit 13 are low, and it can easily be seen that the outputs 13f and 13g of this circuit are high. Thus, no current flows in the coils 6a and 6b of relay 6.
Furthermore, the transistor 44 is blocked by the signal applied to its base by the output of gate 26 which is low.
The transistor 10 is thus also blocked.
lS When, in these conditions, a call signal is transmitted by line A for example, circuit 7 delivers at its output 7c and hence at the input 13a of circuit 13 a high signal and produces a ringing or some other characteristic sound indicating to the user of the apparatus 1 that there is an incoming call.
When the user picks up the handset 2 to reply to this call, contacts 9.1 and 9.2 close. The input 13e of circuit 13, which is now connected to the positive terminal of the current supply 14 by contact 9.2, thus goes high. It can easily be seen that the output of the gate 21 also goes high, as does the output of gate 28. The output of the monostable circuit 39 thus delivers a pulse during which the output 13f of circuit 13 is low, which causes a current pulse to flow in the coil 6a of relay 6. This current pulse switches the relay 6 into its first state, i.e. the state shown in Fig. l, provided of course that the relay is not already in this state, in which case this current pulse would produce no effect.
The pulse produced by the output of the monostable circuit 39 also causes the Q output of flip-flop 38 to go ".,.;~, . . , , ' , ~ 2~:L9~ ~
~' -- 10 --high, provided of course that this output is not already high.
Furthermore, when the output of gate 21 goes high as the user lifts the handset 2 off its support, this causes, S via the gate 27, the Q output of the flip-flop 36 to go low.
Finally, when the input 13e of circuit 13 goes high when the user picks up the handset 2, this makes transistor 44 and hence also transistor 10 conductive after a given lapse of time determined by the characteristics of delay circuit 41. This time may for instance be about 500 milliseconds.
From the moment when transistor 10 becomes conductive, the speech circuit S and hence the handset 2 are connected to the line A and the user of the apparatus can begin to converse with the caller.
Line A is thus now engaged, and the output llc of circuit 11, which previously was low, goes high, as does the input 13c of circuit 13. When the input 13c of circuit ; 2013 goes high, the gates 21 and 22 are blocked via the inverter 31. Hence, in the event of the input 13b of circuit 13 going high in response to another incoming call on line B, this cannot cause a further switching of the relay 6 that would have the effect of breaking the connection just set up between line A and speech circuit 5.
This going high of the input 13e has no effect on gate 23 which is already blocked by the low signal it receives from the Q output of flip-~lop 36. -30When the user of apparatus 1 puts down the handset 2 at the end of the conversation, contact 9.2 opens again and the input 13e of circuit 13 returns to low~ ~-This going low of the input 13e causes, via inverter -32, the Q output of flip-fIop ~6 to go high again and, 35via the timing circuit 41 and gate 26, the transistor 44 and thus the transistor 10 to be blocked. Line A is 9 1 ~ ~
thus once again free and the output llc of circuit 11 goes low again.
It can be seen that the circuit 13 and the apparatus 1 are once again in the same state as before receiving the incoming call signal on line A, possibly with the sole exception of flip-flop 38 and relay 6 which both remain in the state they took when the user lifted up the handset 2.
If, in these conditions, a new incoming call signal is transmitted to the apparatus 1, but this time by line B, it can easily be seen that when the user lifts up the handset 2 to reply to this call, it will be the output of monostable circuit 40 that delivers a pulse.
During this pulse, the output 13g of circuit 13 is low which causes a current pulse to flow in the coil 6b of relay 6. The latter thus goes to its second state. Also, the pulse produced by the output of monostable circuit 40 causes flip-flop 38 to switch to the state in which its Q
output is low.
Lastly, as in the above-described case where the incoming call signal is transmitted by line A, the Not-Q
output of flip-flop 36 goes low when the user lifts up the handset 2 and, after a given time, transistors 44 and 10 become conductive.
The speech circuit 5, and hence the handset 2, are thus connected to line B and the user of the apparatus 1 can converse with the caller. As in the previous case, the output llc of circuit ll goes high in response to the ! 1~ engaged state of the line to which apparatus 1 is connected, which in this instance is line B.
Still as in the previous example, when the user places the handset 2 back on its support at the end of the conversation, the circuit 13 and the apparatus 1 are both in the state they were in before the conversation began, with the sole exception of flip-flop 38 and relay 6 which D~
remain in the state they took when the user lifted the handset 2.
When both lines A and B simultaneously transmit a call signal, the two inputs 13a and 13b of circuit 13 are both high. But thelow state which is then present at the output of inverter 30 blocks the gate 22. Therefore, when the user of apparatus 1 lifts up the handset 2, circuit 13 operates in the same manner as described above in the case when only line A transmits a call.
If, when the user of apparatus 1 replaces handset 2 on its support at the end of the ~unication establishedin this way, there is still, or again, a call signal on line b, the circuit 13 operates in the same way as described above in the case when only a single call is transmitted by line B.
It has been seen above that when the user of apparatus 1 lifts up handset 2 to reply to an incoming call on line A, the Q output of flip-flop 38 goes high and remains high after the end of the oom~nication. In a similar manner, the Q output of flip-flop 38 goes low when the user of the apparatus replies to an incoming call on line B and remainsin this state at the end of the c~nication. It will be seen below that when the user of apparatus 1 makes an outgoing call, the Q output of flip-flop 38 also goes high or low according to whether this outgoing call is being made, in a way that will be described later, on line A or on line B, and that the logic state of this output is . .
not modified at the end of this outgoing call.
Between communications, the state of the ~ output of flip-flop 38 thus always indicates with which line, A or B, apparatus 1 was connected during the last communication.
This feature is used to automatically connect apparatus 1 to a free line, if there is one, when the user of apparatus l lifts up handset 2 to make an outgoing call.
It will be assumed to begin with that neither of telephones 15 and 16 connected respectively to lines A and B is in use and, of course, that there is no call signal " 2 ~
on either line. It will also be assumed that relay 6 is in its first state.
In these conditions, when the user of apparatus 1 lifts up handset 2 for the purpose of making a call, the closing of contact 9.1 causes the relatively high voltage across the two wires of line A to be applied to the terminals lla and llb of circuit 11. The output llc of circuit 11 and the input 13e of circuit 13 thus go low, thereby blocking the gate 23. Because the outputs 7c and 8c of call circuits 7 and 8, and hence the inputs 13a and 13b of circuit 13, are low as well, gates 21 and 22 are also blocked.
It can easily be seen that in this case, neither of monostable circuits 39 and 40 produces a pulse and the state of rela~ 6 remains unmodified. However, as in the above-described examples, transistors 94 and 10 become conductive when the output of delay circuit 41 goes high.
Speech circuit 5 and handset 2 are thus now connected to line A which goes from free to enga~ed state. The output llc of circuit 11 thus goes high, ~ut this change iswithout consequence because gate 23 is blocked by the low signal provided by the output of inverter 33 in response to the high signal at the output of delay circuit 41.
The user of apparatus 1 may thus begin to select the number he wishes to call by acting on selector device 12, after hearing the usual sound signal from the telephone exchange indicating that the exchange is ready to record the selected number.
As mentioned above, the output 12a of selector device 12 produces a given number of pulses each time one of the selector keys is actuated.
Each of these pulses causes, via inverter 34 and gate 26, transistors 49 and 10 to be blocked. The circuit interruptions caused by the successive blockings of transistor 10 are detected in a well known manner by the exchange to which line A is connected and then enable the - 14 - 2~9~
exchange to connect the apparatus 1 and the subscriber being called.
When the user of apparatus 1 places handset 2 back on the support at the end of the conversation, apparatus 1 and circuit 13 are in the same state as they were in before the user lifted up handset 2.
It can easily be seen that if the relay 6 is in its second state, with its contacts 6.1 and 6.2 open and its contacts 6.3 and 6.4 closed, when the user of apparatus 1 lifts up the handset to make a call, operation of the circuit 13 is exactly the same as in the just-described case, except that in this case the connection is made via line B.
When the user of the apparatus lifts up handset 2 for the purpose of making a call, and the relay 6 is in its first state but line A is already engaged by a connection with the telephone 15, the closing of contact 9.1 causes the voltage across the two wires of line A to be applied to the terminals lla and llb of circuit 11. As line A is engaged, this voltage is relatively low and the output llc of circuit 11 as well as the input 13c of circuit 13 thus go high, as does the output of gate 23.
This output of gate 23 remains high for only a very short instant, because this high state causes the Q
output of flip-flop 37 to go low which, in turn, causes the output of gate 23 to go low.
This output of gate 23 therefore delivers a pulse that is transmitted to the input of monostable circuit 40 via the gates 25 and 29. This is because, at this instant, the Q output of flip-flop 38 is high due to the relay 6 being in its first state.
Monostable circuit 40 thus produces a pulse which firstly causes relay 6 to switch to its second position where its contacts 6.1 and 6.2 are open and where its contacts 6.3 and 6.4 are closed and, secondly, causes the Q output of flip-flop 38 to go low.
- 15 - 2~9~6~
When transistors 44 and 10 become conductive in response to the output of delay circuit 41 going high, the speech circuit 5 is thus connected to line B.
If the latter is free, the user of the apparatus 1 may then select, by way of circuit 12, the number of the subscriber he wants to call after having received the usual sound signal from the exchange.
If line B is engaged by a connection with telephone 16, the user of apparatus 1 may then, if he so wishes, cut in on the conversation and request that the latter be interrupted and that the line be made free.
- If he does not wish to avail himself of this possibility, the user of apparatus 1 may simply place handset 2 back on its support when he realizes that the : 15 line to which he is connected is already engaged.
In any event, when the user places handset 2 on its support, apparatus 1 remains in the state it is in.
It can easily be seen that when the user of apparatus 1 picks up handset 2 for the purpose of making a call, and relay 6 is in its second state but line B is already engaged by a connection with telephone 16, the circuit 13 operates in a similar manner to that described above. In this case however, the pulse produced by the output of gate 23 is fed to the input of monostable circuit 39 via gates 24 and 28 because it is the Q output of flip-flop 38 which is high.
The pulse then produced by monostable circuit 39 causes the relay 6 to switch to its first state and .speech circuit 5 is thus connected to line A when transistors 9q and 10 become conductive.
As in the previous case, if line A is free, the user of apparatus 1 may then select the number of the subscriber he wants to call, and if line A is engaged by a connection with tele-.~hone 15, he mav cut in on the conversation and request that the line be made free, or place handset ~ back on its support.
- 16 - 2~ 6 Control circuit 13 may of course be arranged in such a manner that when the two lines A and B are engaged by connections with telephones 15 and 16, respectively, i.e.
when the output llc of voltage detection circuit 11 goes 5 high again as relay 6 changes state, transistor 10 is not made conductive, and handset 2 is thus not connected to either of lines A and B. In such a case, which has not been illustrated, circuit 13 may be arranged in such a manner as to produce an acoustic and/or optical signal to warn the user of apparatus 1 that he cannot make his call because both lines A and B are engaged.
In the embodiment of the apparatus according to the invention shown in Fig. 4, the apparatus, designated by 101, comprises most of the elements of the apparatus of Fiq. 1. These elements are designated by the same references in the two Figures and will not be described again here.
Like apparatus 1 of Fig. 1, apparatus 101 comprises two terminals lOla and lOlb connected to a first telephone line A, to which is also connected another telephone 15, and two terminals lOlc and lOld connected to a second telephone line B to which is also connected another telephone 16.
Apparatus 101 comprises a second handset 102 comprising an earphone 103 and a micxophone 104 that are connected in conventional manner to a speech circuit 105.
Still like apparatus 1, apparatus 101 comprises a bistable relay, designated by 106, having two coils 106a ` ! and 106b of which one terminal is connected to the positive terminal of current supply 14. Relay 106 includes four switching contacts, 106.1, 106.2, 106.3 and 106.4, whose common terminals are respectively connected to the inputs lOla, lOlb, lOlc and lOld of apparatus 101 The non-common terminals of contacts 106.1 to 106.q are connected to one another and to the other elements of ~he apparatus~as shown in Fig. 4.
~` - 17 - 20~
: It can be seen in Fig. 4 that when the relay 106 is in its first state, as shown , line A is connected to speech circuit 5 via contact 9.1 and transistor 10. It can also be seen that, in the same state of relay 106, line B
5 is connected to the speech circuit lOS via a contact 109.1 and a transistor 110.
Contact 109.1 is similar to contact 9.1, i.e. it is open when handset 102 is placed on its support and closed when handset 102 is lifted from the support to be used.
~: 10 Likewise,~transistor 110 is similar to transistor 10, ~: i.e. it is al:so:a pnp transistor and is also made conductive, in circumstances that~will be described below, when a connection must be made with handset 102.
Fig. 4 also shows that when relay 106 is in its 15 second state, that is line A which is connected to speech circuit lOS via contact 109.1 and transistor 110, and that is line B wich is connected to speech circuit 5 : ~ via contact 9.1 and transistor 10.
Apparatus 101 of Fig. 4 further comprises a second 20 voltage detector circuit 111 similar to voltage detector circuit 11. The terminals llla and lllb of the circuit 111 are respectively connected to the second terminal of contact 109.1 and to the first non-common terminal of contact 106.4.
Apparatus 101 further comprises a control circuit 113 having inputs~113a to 113e respectively connected, like inputs 13a to 13e of circuit 13 in Fig. l, to the output 7c, 8c llc and 12c of call circuits 7 and 8, voltage detector 11 and selection pulsesgenerating circuit 12, and to the second 30 terminal of contact 9.2.
Control circuit 113 also includes two outputs 113f : and 113g respectively connected to the second terminals of coils 106a and 106b, and an output 113h connected to the base of transistor 10.
- 18 - 2~
Control circuit 113 also includes two inputs 113i and 113j respectively connected to the output lllc of voltage detector circuit 111 and to one terminal of a contact 109.2 that is mechanically connected to the contact 109.1 so as to be opened and closed at the same time as the latter. The other terminal of contact 109.2 is connected to the positive terminal of current supply 14.
Finally, control circuit 113 comprises an output 113k connected to the base of transistor 110.
The configuration of control circuit 113 will not be described in detail because it can easily be deduced from the *ollowing description of the operation of apparatus 101 .
To begin with, it will be assumed that handsets 2 and 102 are both placed on their respective supports.
When a call signal comes in on line A and a user lifts up handset 2 to reply to this call, circuit 113 reacts to the highs it then receives on its inputs 113a and 113e by supplying a current pulse to the coil 106a of relay 106 which thus goes to its first state unless of course it is already in that state.
Furthermore, a short instant after the closing of contact 9 2, circuit 113 puts the transistor 10 into its conductive state. Handset 2 is therefore now connected to line A via speech circuit 5.
If the user lifts up handset 102 to reply to a call signal on line B, circuit 113 also supplies a current pulse to the coil 106a of relay 106 in response to the highs it receives on its inputs 113b and 113j and, a short instant after the closing of contact 109.2, puts the transistor lI0 in its conductive state. Relay 106 therefore also switches to its first state, if it was not already in that state, and handset 102 is connected to line B via speech circuit 105.
Likewise, if the user lifts up handset 2 to reply to a call signal on line B, or lifts up handset 102 to reply . r~ - 19 - 2~
to a call signal on line A, circuit 113 reacts to the highs it receives on its inputs 113b and 113e, or on its inputs 113a and 113j, by supplying a current pulse to the coil 106b of relay 106, so that the latter switches to its S second state if it was not already in that state.
Furthermore, circuit 113 makes transistor 10 conductive, in the first case, or makes transistor 110 conductive, in the second case, whereby handset 2 is connected to line B or handset 102 is connected to line A.
When a user wishes to use the apparatus 101 to make a call, the following different situations may arise:
1. The user lifts up the handset 2 while:
- line A is free and relay 106 is in its first state ; or lS - line B is free and relay 106 is in its second state ; or - lines A and B are both free.
In this case, the output llc of voltage detector circuit 11 goes low in response to the relatively high voltage that is applied to the terminals lla and llb of circuit 11 following the closing of contact 9.1, whatever may be the state of the relay 106. Circuit 113 thus delivers no current pulse to the coils 106a and 106b of relay 106 wh;ch, therefore, does not change state. However, a short instant after the closing of contact 9.2, circuit 113 makes transistor 10 conductive, thus connecting handset 2 to line A, if relay 106 is in its first state, or to line B, if relay 106 is in its second state. Moreover, circuit li3 indirectly connects its input 113d to its output 113h so that the transistor is once again blocked in response to each of the pulses produced by selection pulses generator circuit 12 when the user actuates its keys to select the number he wishes to call.
2. The user picks up handset 102 while :
- line A is free and relay 106 is in its second state ;
~ 20 - 2~ &~
- line B iS free and relay 106 is in its first state ; or - lines A and B are both free.
In this case, it is the output lllc of voltage detector circuit 111 which goes low in response to the relatively high voltage applied to its terminals llla and lllb following the closing of contact 109.2, whatever may be the state of relay 106. In this case, circuit 113 also delivers no pulse to the coils 106a and 106b of relay 106 but, a short instant after the closing of contact 109.2, circuit 113 makes transistor 110 conductive, thus connecting handset 102 to line B if relay 106 is in its first state, or to line A if relay 106 is in its second state. Moreover, circuit 113 indirectly connects its input 113d to its output 113k so that when the user selects the number to be called, transistor 110 is blocked in response to each pulse produced by the output 12a of circuit 12.
Backaround of the Tnvention The present invention concerns a telephone apparatus adapted to be connected to a plurality of telephone lines each able to have a free state and an engaged state and S each able to transmit a call signal, including an electro-acoustic unit comprising a microphone and an earphone and switching means responsive to any one of said call signals to selectively connect said electro-acoustic unit to the line that transmits this call signal.
Such apparatus are well known. Thus, for example, the I Swiss telephone administration offers for rental to its ¦ subscribers an accessory called "Accessory for two lines Tritel BZ 85.22" that can be connected to two telephone lines and to a conventional telephone set to form with it an apparatus corresponding to the definition given above.
When a call signal is received on one of the two lines connected to the apparatus, the above-mentioned accessory automatically sets up a connection between this line and the telephone set so that when the set's user lifts up the handset to reply to the call, he is ; immediately connected to the caller without having to make any further manipulation.
If one of the two lines has been designated as a priority line and the above-mentioned accessory has been set accordingly, the handset of the telephone, on being picked up by the user to make a call, will always be connected to this priority line.
Otherwise, to make a call, the user must select one of the two lines by actuating a push button.
It is more and more frequent for two or more telephone sets to be connected in parallel on the same subscriber's line, these different sets being for example situated in different rooms of the same appartment or house.
In such a case, the chances are that when the user of an apparatus such as that described above picks up his ..
, :
:-' 2~9~ ~6 telephone handset to make a call, the handset is connected to a line that is already engaged by another call. This user must then manually select the other line to be able to make his call.
Summ~ry of the Tnvention An object o~ the invention is to propose a telephone apparatus of the above-defined kind but which does not have this drawback, i.e. whose handset is automatically connected to a free line, if there is one, when the user picks it up to make a call.
This object is achieved by the claimed apparatus.
Brief nescri~tion of the Drawinas The invention will now be described with reference to the accompanying drawings in which:
- Figure 1 schematically shows a first embodiment of the apparatus according to the invention ;
- Figure 2 is the block diagram of a control circuit that can be used in the apparatus of Figure 1 ;
! - Figure 3 is the block diagram of a line voltage ~20 detector that can be used in the circuit of Figure 2 ; and I- Figure 4 schematically shows a second embodiment of the apparatus according to the invention ~etailed Descrip~ion The telephone apparatus according to the invention shown schematically in Figure 1 by reference 1 comprises four connection terminals la, lb, lc and ld. Terminals la and lb are adapted to be connected to two wires A1 and A2 that together form a telephone line A connected at its other end to a telephone exchange. Terminals lc and ld of the apparatus 1 are connected to two wires B1 and B2 together forming a second telephone line, B, also connected at its other end to a telephone exchange.
The apparatus 1 further comprises, as is conventional, a base (not shown) connected by a cord to a handset 2 comprising an earphone 3 and a microphone 4.
~, ,~....................................... : .
::!:' ,' ' . ,, , `
~.i" ~
,' ~: ',,, ' . ` , .i,.~ ,, ~ :, . j 2~g~
When the handset is not being used, it can be placed on a ¦ support incorporated in the base.
As is also conventional, the handset 4 is connected to the output of a speech circuit 5 by means of which the signals adapted to energize the earphone 3 can be separated from those produced by the microphone 4.
The apparatus 1 also includes a bistable relay 6 comprising two coils 6a and 6b each having a f irst terminal connected to the positive pole of a power supply that will be described below and a second terminal connected to a control circuit that will also be described below.
The relay 6 also comprises four unipolar contacts 6.1, 6.2, 6.3 and 6.4 mechanically connected together in such a manner that the contacts 6.1 and 6.2 are always in the same closed or open state, and the contacts 6.3 and 6.4 are always in the opposite state to contacts 6.1 and 6.2.
The relay 6 is furthermore arranged in such a manner that the contacts 6.1 to 6.4 are placed in the state illustrated in Figure 1 by a current pulse delivered to its coil 6a, and in their opposite state by a current pulse delivered to its coil 6b. These two states will ~-arbitrarily be designated as being tne first and second 25 states of relay 6. -The first terminals of contacts 6.1 and 6.2 are respectively connected to the terminals la and lb of the apparatus 1, and to the terminals 7a and 7b of a call circuit 7. -~
This call circuit 7 will not be described in detail here because it is well known. Suffice it to say that, in this example, this circuit is arranged in such a manner that its output 7c produces a logic signal that goes high in response to call signals on the line A and goes low in the absence of these call signals. These high and low logic states will be defined below.
`;
., `
~ 2 ~
Also, the call circuit 7 comprises, in conventional manner, a bell, a vibrator or any other similar device able to produce a characteristic sound or noise in response to the above-mentioned call signals. If required, the circuit 7 may also include a signal lamp that lights up in response to these call signals.
Likewise, the first terminals of contacts 6.3 and 6.4 are respectively connected to the terminals lc and ld of the apparatus 1 and to the terminals 8a and 8b of another call circuit 8.
This circuit 8 is similar to the above-mentioned circuit 7. Like the latter, it comprises an output 8c that produces a logic signal that goes high in response to call signals on line B and goes low in the absence of these lS call signals. Like circuit 7, the circuit 8 also comprises a bell, a vibrator or another similar device able to produce a characteristic sound or noise in response to call signals on line B and, if required, a signal lamp that lights up in response to these call signals.
The second terminal~ of contacts 6.1 and 6.3 are connected together to the first terminal of a contact 9.1 which, in the present example, is actuated by a push rod arranged in the support of handset 2 in such a manner that contact 9.1 is open when the handset 2 is not being used and is at rest on this suppor~, and is open when the handset 2 is lifted off the support with a view to being used.
The second terminal of contact 9.1 is connected to the emitter of a bipolar pnp transistor 10 whose collector is connected to a first terminal Sa of speech circuit 5, and to a first terminal lla of a voltage detector circuit 11 that will be described in detail later.
The second terminals of contacts 6.2 and 6.9 are connected together to a second terminal 5b of speech circuit 5 and to a second terminal llb of the voltage detector circuit 11.
~ 6 - 2 ~
The apparatus 1 of Figure 1 further includes a selection pulsesgenerating-circuit 12 that may for example comprise a keyboard having ten keys numbered 0 to 9 and an electronic circuit whose output constitutes the output 12a of circuit 12 and which is arranged so that this output 12a is normally low and supplies, in response to each actuation of one of the keys, a given number of pulses during which it goes high, the number of pulses corresponding to the number of the actuated key.
The apparatus 1 of Figure l also comprises a control circuit 13, an example of which will be described below.
Circuit 13 has inputs 13a to 13d connected respectively to the outputs 7c, 8c, llc and 12a of circuits 7, 8, 11 and 12, as well as an input 13e connected to a first terminal of a contact 9.2 whose second terminal is connected to the positive pole of the above-mentioned power supply. Like the contact 9.1 to which it is mechanically connected, contact 9.2 is open when the handset 2 is placed on the support of apparatus 1 and is closed when this handset 2 is in use.
The control circuit 13 also has outputs 13f, 13g and 13h respectively connected to the second terminals of relay coils 6a and 6b and to the base of the transistor 10 .
The electrical energy required for operation of the various circuits of the apparatus 1 is supplied by either of the lines A and B via a source lq that may, for example, be a simple voltage stabilizing circuit. The inputs 14a and 19b of this source 14 are respectively connected to the second terminals of contacts 6.1 and 6.3 and to the second terminals of contacts 6.2 and 6.4, so as to be connected to either of lines A and B irrespective of the state of the relay 6.
The outputs 19c and 14d of source 14, which respectively constitute its negative terminal, designated by the sign -, and its positive terminal, designated by ,~ 2~9~
the sign +, are connected to the various circuits of apparatus 1 by connections that have not been shown.
Furthermore, negative terminal 14c is connected to the input terminal 14b and its potential is the reference potential for the entire apparatus 1.
The previously mentioned low and high logic states that will be discussed again below correspond respectively to the potential of the negative terminal 14c and to the potential of the positive terminal 14d of source 14.
Figure l also shows that two further telephones are also connected the one to line A and the other to line B. These two further telephones, designated by lS
and 16, can be of any type and will not be described here.
Figure 2 is the block diagram of an example of the control circuit 13 of Figure 1. This circuit 13 comprises AND gates 21 to 26, OR gates 27 to 29, inverters 30 to 34, RS flip-flops 36 to 38, monostable circuits39 and 40, a delay circuit 41, two inverter amplifiers 42 and 43, an npn bipolar transistor 44, and two resistors 45 and 46.
All of these elements are connected to one another and to the inputs and outputs of circuit 13 that are designated by the same references as in Fig. 1, in the manner shown in Fig. 2. In order not to lengthen unnecessarily the present description, these connections will not be described in detail.
Fig. 3 is a block diagram of an example of the voltage detector circuit of Fig. l.
In this example, this circuit includes two resistors S1 and 52 connected in series between terminals lla and llb. The point of junction of resistors S1 and 52 is connected to the base of an npn bipolar transistor 53 whose emitter is also connected to terminal llb and whose collector is connected to output llc and, via a resistor 54, to the positive terminal of the power supply 14.
:,~.. . . -,; . :................................... .
~",""~. :
j., .. ,,, ~ . . . :
- 8 - 2~
The resistors S1, 52 and 54 are selected in such a manner that transistor 53 is conductive, and hence its output llc is low, when the voltage across the terminals lla and llb is equal to the voltage across the two wires of a telephone line when the latteris free, i.e. for instance about 48 volts, and in such a manner that output llc is high when the voltage across terminals lla and llb is equal to the voltage across the two wires of a telephone line when thelatteris engaged, i.e. for instance about 10 volts.
To understand the operation of the apparatus 1 of Fig. 1, about to be described below in conjunction with the operation of the control circuit 13 of Fig. 2, it should be noted tha L ~ in conventional manner, the Q or lS direct output of each flip-flop 36 to 38 is low or high according to whether a high logic signal is applied to its R input or to its S input, the Q or inverted output of each of flip-flop 36 to 38 being obviously always in the opposite logic state to its Q output.
Is should further be noted that each of the monostable circuits 39 and 40 delivers at its output a pulse of given duration in response to each transition of its input from low to high, i.e. this output is high during the given duration and then reverts to low.
As will be apparent from the following description, this given duration is the duration that the current pulses applied to the coil 6a or coil 6b of the relay 6 must have to switch the relay to its first or to its second state, respectively.
It should further be noted that, again in a conventional way, the output of the delay circuit 41 normally has the same logic state as its input, but that, when its input goes from low to high, the corresponding change of its output takes place only after a given lapse of time.
. ~ 2~
.. g To begin with, it will be assumed that the apparatus 1 is not in use, i.e. that the handset 2 is placed on its support and contacts 9.1 and 9.2 are open, and that telephones 15 and 16 are also not in use.
In these conditions, the input 13a of circuit 13 is kept low because it is connected to the negative terminal of the current supply 14 via resistor 45.
Also, in the same conditions, the other inputs 13a to 13d of circuit 13 are low, and it can easily be seen that the outputs 13f and 13g of this circuit are high. Thus, no current flows in the coils 6a and 6b of relay 6.
Furthermore, the transistor 44 is blocked by the signal applied to its base by the output of gate 26 which is low.
The transistor 10 is thus also blocked.
lS When, in these conditions, a call signal is transmitted by line A for example, circuit 7 delivers at its output 7c and hence at the input 13a of circuit 13 a high signal and produces a ringing or some other characteristic sound indicating to the user of the apparatus 1 that there is an incoming call.
When the user picks up the handset 2 to reply to this call, contacts 9.1 and 9.2 close. The input 13e of circuit 13, which is now connected to the positive terminal of the current supply 14 by contact 9.2, thus goes high. It can easily be seen that the output of the gate 21 also goes high, as does the output of gate 28. The output of the monostable circuit 39 thus delivers a pulse during which the output 13f of circuit 13 is low, which causes a current pulse to flow in the coil 6a of relay 6. This current pulse switches the relay 6 into its first state, i.e. the state shown in Fig. l, provided of course that the relay is not already in this state, in which case this current pulse would produce no effect.
The pulse produced by the output of the monostable circuit 39 also causes the Q output of flip-flop 38 to go ".,.;~, . . , , ' , ~ 2~:L9~ ~
~' -- 10 --high, provided of course that this output is not already high.
Furthermore, when the output of gate 21 goes high as the user lifts the handset 2 off its support, this causes, S via the gate 27, the Q output of the flip-flop 36 to go low.
Finally, when the input 13e of circuit 13 goes high when the user picks up the handset 2, this makes transistor 44 and hence also transistor 10 conductive after a given lapse of time determined by the characteristics of delay circuit 41. This time may for instance be about 500 milliseconds.
From the moment when transistor 10 becomes conductive, the speech circuit S and hence the handset 2 are connected to the line A and the user of the apparatus can begin to converse with the caller.
Line A is thus now engaged, and the output llc of circuit 11, which previously was low, goes high, as does the input 13c of circuit 13. When the input 13c of circuit ; 2013 goes high, the gates 21 and 22 are blocked via the inverter 31. Hence, in the event of the input 13b of circuit 13 going high in response to another incoming call on line B, this cannot cause a further switching of the relay 6 that would have the effect of breaking the connection just set up between line A and speech circuit 5.
This going high of the input 13e has no effect on gate 23 which is already blocked by the low signal it receives from the Q output of flip-~lop 36. -30When the user of apparatus 1 puts down the handset 2 at the end of the conversation, contact 9.2 opens again and the input 13e of circuit 13 returns to low~ ~-This going low of the input 13e causes, via inverter -32, the Q output of flip-fIop ~6 to go high again and, 35via the timing circuit 41 and gate 26, the transistor 44 and thus the transistor 10 to be blocked. Line A is 9 1 ~ ~
thus once again free and the output llc of circuit 11 goes low again.
It can be seen that the circuit 13 and the apparatus 1 are once again in the same state as before receiving the incoming call signal on line A, possibly with the sole exception of flip-flop 38 and relay 6 which both remain in the state they took when the user lifted up the handset 2.
If, in these conditions, a new incoming call signal is transmitted to the apparatus 1, but this time by line B, it can easily be seen that when the user lifts up the handset 2 to reply to this call, it will be the output of monostable circuit 40 that delivers a pulse.
During this pulse, the output 13g of circuit 13 is low which causes a current pulse to flow in the coil 6b of relay 6. The latter thus goes to its second state. Also, the pulse produced by the output of monostable circuit 40 causes flip-flop 38 to switch to the state in which its Q
output is low.
Lastly, as in the above-described case where the incoming call signal is transmitted by line A, the Not-Q
output of flip-flop 36 goes low when the user lifts up the handset 2 and, after a given time, transistors 44 and 10 become conductive.
The speech circuit 5, and hence the handset 2, are thus connected to line B and the user of the apparatus 1 can converse with the caller. As in the previous case, the output llc of circuit ll goes high in response to the ! 1~ engaged state of the line to which apparatus 1 is connected, which in this instance is line B.
Still as in the previous example, when the user places the handset 2 back on its support at the end of the conversation, the circuit 13 and the apparatus 1 are both in the state they were in before the conversation began, with the sole exception of flip-flop 38 and relay 6 which D~
remain in the state they took when the user lifted the handset 2.
When both lines A and B simultaneously transmit a call signal, the two inputs 13a and 13b of circuit 13 are both high. But thelow state which is then present at the output of inverter 30 blocks the gate 22. Therefore, when the user of apparatus 1 lifts up the handset 2, circuit 13 operates in the same manner as described above in the case when only line A transmits a call.
If, when the user of apparatus 1 replaces handset 2 on its support at the end of the ~unication establishedin this way, there is still, or again, a call signal on line b, the circuit 13 operates in the same way as described above in the case when only a single call is transmitted by line B.
It has been seen above that when the user of apparatus 1 lifts up handset 2 to reply to an incoming call on line A, the Q output of flip-flop 38 goes high and remains high after the end of the oom~nication. In a similar manner, the Q output of flip-flop 38 goes low when the user of the apparatus replies to an incoming call on line B and remainsin this state at the end of the c~nication. It will be seen below that when the user of apparatus 1 makes an outgoing call, the Q output of flip-flop 38 also goes high or low according to whether this outgoing call is being made, in a way that will be described later, on line A or on line B, and that the logic state of this output is . .
not modified at the end of this outgoing call.
Between communications, the state of the ~ output of flip-flop 38 thus always indicates with which line, A or B, apparatus 1 was connected during the last communication.
This feature is used to automatically connect apparatus 1 to a free line, if there is one, when the user of apparatus l lifts up handset 2 to make an outgoing call.
It will be assumed to begin with that neither of telephones 15 and 16 connected respectively to lines A and B is in use and, of course, that there is no call signal " 2 ~
on either line. It will also be assumed that relay 6 is in its first state.
In these conditions, when the user of apparatus 1 lifts up handset 2 for the purpose of making a call, the closing of contact 9.1 causes the relatively high voltage across the two wires of line A to be applied to the terminals lla and llb of circuit 11. The output llc of circuit 11 and the input 13e of circuit 13 thus go low, thereby blocking the gate 23. Because the outputs 7c and 8c of call circuits 7 and 8, and hence the inputs 13a and 13b of circuit 13, are low as well, gates 21 and 22 are also blocked.
It can easily be seen that in this case, neither of monostable circuits 39 and 40 produces a pulse and the state of rela~ 6 remains unmodified. However, as in the above-described examples, transistors 94 and 10 become conductive when the output of delay circuit 41 goes high.
Speech circuit 5 and handset 2 are thus now connected to line A which goes from free to enga~ed state. The output llc of circuit 11 thus goes high, ~ut this change iswithout consequence because gate 23 is blocked by the low signal provided by the output of inverter 33 in response to the high signal at the output of delay circuit 41.
The user of apparatus 1 may thus begin to select the number he wishes to call by acting on selector device 12, after hearing the usual sound signal from the telephone exchange indicating that the exchange is ready to record the selected number.
As mentioned above, the output 12a of selector device 12 produces a given number of pulses each time one of the selector keys is actuated.
Each of these pulses causes, via inverter 34 and gate 26, transistors 49 and 10 to be blocked. The circuit interruptions caused by the successive blockings of transistor 10 are detected in a well known manner by the exchange to which line A is connected and then enable the - 14 - 2~9~
exchange to connect the apparatus 1 and the subscriber being called.
When the user of apparatus 1 places handset 2 back on the support at the end of the conversation, apparatus 1 and circuit 13 are in the same state as they were in before the user lifted up handset 2.
It can easily be seen that if the relay 6 is in its second state, with its contacts 6.1 and 6.2 open and its contacts 6.3 and 6.4 closed, when the user of apparatus 1 lifts up the handset to make a call, operation of the circuit 13 is exactly the same as in the just-described case, except that in this case the connection is made via line B.
When the user of the apparatus lifts up handset 2 for the purpose of making a call, and the relay 6 is in its first state but line A is already engaged by a connection with the telephone 15, the closing of contact 9.1 causes the voltage across the two wires of line A to be applied to the terminals lla and llb of circuit 11. As line A is engaged, this voltage is relatively low and the output llc of circuit 11 as well as the input 13c of circuit 13 thus go high, as does the output of gate 23.
This output of gate 23 remains high for only a very short instant, because this high state causes the Q
output of flip-flop 37 to go low which, in turn, causes the output of gate 23 to go low.
This output of gate 23 therefore delivers a pulse that is transmitted to the input of monostable circuit 40 via the gates 25 and 29. This is because, at this instant, the Q output of flip-flop 38 is high due to the relay 6 being in its first state.
Monostable circuit 40 thus produces a pulse which firstly causes relay 6 to switch to its second position where its contacts 6.1 and 6.2 are open and where its contacts 6.3 and 6.4 are closed and, secondly, causes the Q output of flip-flop 38 to go low.
- 15 - 2~9~6~
When transistors 44 and 10 become conductive in response to the output of delay circuit 41 going high, the speech circuit 5 is thus connected to line B.
If the latter is free, the user of the apparatus 1 may then select, by way of circuit 12, the number of the subscriber he wants to call after having received the usual sound signal from the exchange.
If line B is engaged by a connection with telephone 16, the user of apparatus 1 may then, if he so wishes, cut in on the conversation and request that the latter be interrupted and that the line be made free.
- If he does not wish to avail himself of this possibility, the user of apparatus 1 may simply place handset 2 back on its support when he realizes that the : 15 line to which he is connected is already engaged.
In any event, when the user places handset 2 on its support, apparatus 1 remains in the state it is in.
It can easily be seen that when the user of apparatus 1 picks up handset 2 for the purpose of making a call, and relay 6 is in its second state but line B is already engaged by a connection with telephone 16, the circuit 13 operates in a similar manner to that described above. In this case however, the pulse produced by the output of gate 23 is fed to the input of monostable circuit 39 via gates 24 and 28 because it is the Q output of flip-flop 38 which is high.
The pulse then produced by monostable circuit 39 causes the relay 6 to switch to its first state and .speech circuit 5 is thus connected to line A when transistors 9q and 10 become conductive.
As in the previous case, if line A is free, the user of apparatus 1 may then select the number of the subscriber he wants to call, and if line A is engaged by a connection with tele-.~hone 15, he mav cut in on the conversation and request that the line be made free, or place handset ~ back on its support.
- 16 - 2~ 6 Control circuit 13 may of course be arranged in such a manner that when the two lines A and B are engaged by connections with telephones 15 and 16, respectively, i.e.
when the output llc of voltage detection circuit 11 goes 5 high again as relay 6 changes state, transistor 10 is not made conductive, and handset 2 is thus not connected to either of lines A and B. In such a case, which has not been illustrated, circuit 13 may be arranged in such a manner as to produce an acoustic and/or optical signal to warn the user of apparatus 1 that he cannot make his call because both lines A and B are engaged.
In the embodiment of the apparatus according to the invention shown in Fig. 4, the apparatus, designated by 101, comprises most of the elements of the apparatus of Fiq. 1. These elements are designated by the same references in the two Figures and will not be described again here.
Like apparatus 1 of Fig. 1, apparatus 101 comprises two terminals lOla and lOlb connected to a first telephone line A, to which is also connected another telephone 15, and two terminals lOlc and lOld connected to a second telephone line B to which is also connected another telephone 16.
Apparatus 101 comprises a second handset 102 comprising an earphone 103 and a micxophone 104 that are connected in conventional manner to a speech circuit 105.
Still like apparatus 1, apparatus 101 comprises a bistable relay, designated by 106, having two coils 106a ` ! and 106b of which one terminal is connected to the positive terminal of current supply 14. Relay 106 includes four switching contacts, 106.1, 106.2, 106.3 and 106.4, whose common terminals are respectively connected to the inputs lOla, lOlb, lOlc and lOld of apparatus 101 The non-common terminals of contacts 106.1 to 106.q are connected to one another and to the other elements of ~he apparatus~as shown in Fig. 4.
~` - 17 - 20~
: It can be seen in Fig. 4 that when the relay 106 is in its first state, as shown , line A is connected to speech circuit 5 via contact 9.1 and transistor 10. It can also be seen that, in the same state of relay 106, line B
5 is connected to the speech circuit lOS via a contact 109.1 and a transistor 110.
Contact 109.1 is similar to contact 9.1, i.e. it is open when handset 102 is placed on its support and closed when handset 102 is lifted from the support to be used.
~: 10 Likewise,~transistor 110 is similar to transistor 10, ~: i.e. it is al:so:a pnp transistor and is also made conductive, in circumstances that~will be described below, when a connection must be made with handset 102.
Fig. 4 also shows that when relay 106 is in its 15 second state, that is line A which is connected to speech circuit lOS via contact 109.1 and transistor 110, and that is line B wich is connected to speech circuit 5 : ~ via contact 9.1 and transistor 10.
Apparatus 101 of Fig. 4 further comprises a second 20 voltage detector circuit 111 similar to voltage detector circuit 11. The terminals llla and lllb of the circuit 111 are respectively connected to the second terminal of contact 109.1 and to the first non-common terminal of contact 106.4.
Apparatus 101 further comprises a control circuit 113 having inputs~113a to 113e respectively connected, like inputs 13a to 13e of circuit 13 in Fig. l, to the output 7c, 8c llc and 12c of call circuits 7 and 8, voltage detector 11 and selection pulsesgenerating circuit 12, and to the second 30 terminal of contact 9.2.
Control circuit 113 also includes two outputs 113f : and 113g respectively connected to the second terminals of coils 106a and 106b, and an output 113h connected to the base of transistor 10.
- 18 - 2~
Control circuit 113 also includes two inputs 113i and 113j respectively connected to the output lllc of voltage detector circuit 111 and to one terminal of a contact 109.2 that is mechanically connected to the contact 109.1 so as to be opened and closed at the same time as the latter. The other terminal of contact 109.2 is connected to the positive terminal of current supply 14.
Finally, control circuit 113 comprises an output 113k connected to the base of transistor 110.
The configuration of control circuit 113 will not be described in detail because it can easily be deduced from the *ollowing description of the operation of apparatus 101 .
To begin with, it will be assumed that handsets 2 and 102 are both placed on their respective supports.
When a call signal comes in on line A and a user lifts up handset 2 to reply to this call, circuit 113 reacts to the highs it then receives on its inputs 113a and 113e by supplying a current pulse to the coil 106a of relay 106 which thus goes to its first state unless of course it is already in that state.
Furthermore, a short instant after the closing of contact 9 2, circuit 113 puts the transistor 10 into its conductive state. Handset 2 is therefore now connected to line A via speech circuit 5.
If the user lifts up handset 102 to reply to a call signal on line B, circuit 113 also supplies a current pulse to the coil 106a of relay 106 in response to the highs it receives on its inputs 113b and 113j and, a short instant after the closing of contact 109.2, puts the transistor lI0 in its conductive state. Relay 106 therefore also switches to its first state, if it was not already in that state, and handset 102 is connected to line B via speech circuit 105.
Likewise, if the user lifts up handset 2 to reply to a call signal on line B, or lifts up handset 102 to reply . r~ - 19 - 2~
to a call signal on line A, circuit 113 reacts to the highs it receives on its inputs 113b and 113e, or on its inputs 113a and 113j, by supplying a current pulse to the coil 106b of relay 106, so that the latter switches to its S second state if it was not already in that state.
Furthermore, circuit 113 makes transistor 10 conductive, in the first case, or makes transistor 110 conductive, in the second case, whereby handset 2 is connected to line B or handset 102 is connected to line A.
When a user wishes to use the apparatus 101 to make a call, the following different situations may arise:
1. The user lifts up the handset 2 while:
- line A is free and relay 106 is in its first state ; or lS - line B is free and relay 106 is in its second state ; or - lines A and B are both free.
In this case, the output llc of voltage detector circuit 11 goes low in response to the relatively high voltage that is applied to the terminals lla and llb of circuit 11 following the closing of contact 9.1, whatever may be the state of the relay 106. Circuit 113 thus delivers no current pulse to the coils 106a and 106b of relay 106 wh;ch, therefore, does not change state. However, a short instant after the closing of contact 9.2, circuit 113 makes transistor 10 conductive, thus connecting handset 2 to line A, if relay 106 is in its first state, or to line B, if relay 106 is in its second state. Moreover, circuit li3 indirectly connects its input 113d to its output 113h so that the transistor is once again blocked in response to each of the pulses produced by selection pulses generator circuit 12 when the user actuates its keys to select the number he wishes to call.
2. The user picks up handset 102 while :
- line A is free and relay 106 is in its second state ;
~ 20 - 2~ &~
- line B iS free and relay 106 is in its first state ; or - lines A and B are both free.
In this case, it is the output lllc of voltage detector circuit 111 which goes low in response to the relatively high voltage applied to its terminals llla and lllb following the closing of contact 109.2, whatever may be the state of relay 106. In this case, circuit 113 also delivers no pulse to the coils 106a and 106b of relay 106 but, a short instant after the closing of contact 109.2, circuit 113 makes transistor 110 conductive, thus connecting handset 102 to line B if relay 106 is in its first state, or to line A if relay 106 is in its second state. Moreover, circuit 113 indirectly connects its input 113d to its output 113k so that when the user selects the number to be called, transistor 110 is blocked in response to each pulse produced by the output 12a of circuit 12.
3. The user of apparatus 101 picks up handset 2 while relay 106 is in its first state and line A is already engaged by a connection with telephone 15.
In this case, the output llc of voltage detector circuit 11, and hence the input 113c of circuit 113 go high in response to the relatively low voltage applied to the terminals lla and llb of circuit by the closing of contact 9.1.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is low because handset 102 is not in use, circuit 113 delivers a current pulse to the coil 106b of relay 106 which thus takes its second state.
As in case 1 above, circuit 113 also makes transistor 10 conductive a short instant after the closing of contact 9.2 and indirectly connects its input 113d to its output 113h. Handset 2 is thus connected to line B via speech circuit 5.
- 21 - 2~ 6~
If line B is free, the user may then select the number to be called. If, however, line B is already engaged by a call with telephone 16, the user of apparatus 101 may cut in on this call to request that the line be freed, or place handset 2 back on its support.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is high because the handset 102 is already in use, circuit 113 does not ; deliver a pulse to the coil 106b of relay 106 in order not to interrupt the ongoing caIl with handset 102 via line B.
Relay 106 thus stays in its first state and, when circuit Il3 makes transistor lO conductive a short instant after the contact 9.2 is closed, handset 2 is connected to line A. The user of apparatus lOl may therefore cut in on the l5~ ongoing call on line A to request that this line be freed, or place handset 2 back on its support.
In this case, the output llc of voltage detector circuit 11, and hence the input 113c of circuit 113 go high in response to the relatively low voltage applied to the terminals lla and llb of circuit by the closing of contact 9.1.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is low because handset 102 is not in use, circuit 113 delivers a current pulse to the coil 106b of relay 106 which thus takes its second state.
As in case 1 above, circuit 113 also makes transistor 10 conductive a short instant after the closing of contact 9.2 and indirectly connects its input 113d to its output 113h. Handset 2 is thus connected to line B via speech circuit 5.
- 21 - 2~ 6~
If line B is free, the user may then select the number to be called. If, however, line B is already engaged by a call with telephone 16, the user of apparatus 101 may cut in on this call to request that the line be freed, or place handset 2 back on its support.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is high because the handset 102 is already in use, circuit 113 does not ; deliver a pulse to the coil 106b of relay 106 in order not to interrupt the ongoing caIl with handset 102 via line B.
Relay 106 thus stays in its first state and, when circuit Il3 makes transistor lO conductive a short instant after the contact 9.2 is closed, handset 2 is connected to line A. The user of apparatus lOl may therefore cut in on the l5~ ongoing call on line A to request that this line be freed, or place handset 2 back on its support.
4. The user of the apparatus picks up handset 102 while relay 106 is in its first state, and line B is ; already engaged by a cal~l with telephone 16.
In this case, the output lllc of circuit 111, and hence the input~113i of circuit 113 go high in response to the relatively low voltage applied to the terminals llla and~lllb of circuit 111 by the closing of contact 109.1.
; ` If, at the moment when the input 113c of circuit 113 ; 25 goes high, the input 113e of circuit 113 is low because handset 2 is not in use, circuit 113 deIivers a current pulse to ~the coil 106b of relay 106 which thus takes its second state.
As in case 2 above, the circuit 113 also makes the transistor 110 conductive a short instant after contact 109.2 is closed, and indirectly connects its input 113d to its output 113k. Handset 1~2 is therefore connected to line A via speech circuit lOS.
If line A is free, the user may therefore select the number to be called. If, however, line A is alreaay engaged by a : ::-. ~
- 22 - 2~ J
call on telephone 15, the user of apparatus 101 may cut in on this call to request that the line be freed, or place handset 102 back on its support.
If, at the moment when the input 113i of circuit 113 goes high, the input 113c of circuit 113 is high because handset 2 is already in use, circuit 113 does not deliver a pulse to the coil 106b of relay 106, in order not to interrupt the ongoing call with handset 2 via line A. Relay 106 thus stays in its first state and when circuit 113 makes transistor 110 conductive an instant after contact 109.2 is closed, handset 102 is connected to line B. The user of apparatus 101 may then cut in on the ongoing call on line B to request that the line be freed, or may place the handset 102 back on its support.
In this case, the output lllc of circuit 111, and hence the input~113i of circuit 113 go high in response to the relatively low voltage applied to the terminals llla and~lllb of circuit 111 by the closing of contact 109.1.
; ` If, at the moment when the input 113c of circuit 113 ; 25 goes high, the input 113e of circuit 113 is low because handset 2 is not in use, circuit 113 deIivers a current pulse to ~the coil 106b of relay 106 which thus takes its second state.
As in case 2 above, the circuit 113 also makes the transistor 110 conductive a short instant after contact 109.2 is closed, and indirectly connects its input 113d to its output 113k. Handset 1~2 is therefore connected to line A via speech circuit lOS.
If line A is free, the user may therefore select the number to be called. If, however, line A is alreaay engaged by a : ::-. ~
- 22 - 2~ J
call on telephone 15, the user of apparatus 101 may cut in on this call to request that the line be freed, or place handset 102 back on its support.
If, at the moment when the input 113i of circuit 113 goes high, the input 113c of circuit 113 is high because handset 2 is already in use, circuit 113 does not deliver a pulse to the coil 106b of relay 106, in order not to interrupt the ongoing call with handset 2 via line A. Relay 106 thus stays in its first state and when circuit 113 makes transistor 110 conductive an instant after contact 109.2 is closed, handset 102 is connected to line B. The user of apparatus 101 may then cut in on the ongoing call on line B to request that the line be freed, or may place the handset 102 back on its support.
5. The user of apparatus 101 lifts up handset 2 while relay 106 is in its second state and line B is already engaged by a call with telephone 16.
In this case, as in case 3 above, the output llc of voltage detector circuit 11 and thus the input 113c of circuit 113 go high in response to the closing of contact 9.1.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is low because handset 102 is not in use, circuit 113 delivers a current pulse to the coil 106a of relay 106 which thus takes its first state.
As in case 1 above, circuit 113 also makes transistor 10 conductive a short instant after contact 9.2 is closed, and indirectly connects its input 113d to its output 113k.
Handset 2 is thus connected to line A via speech circuit 5.
If line A is free, the user may then select the number to be called. If however, line A is already engaged by a call with telephone 15, the user of apparatus 101 may cut in on this call to request that the line be freed, or may place handset 2 back on its support.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is high because the handset 102 is already in use, the circuit 113 delivers ~pulse to the coil 106a of relay 106 in order not to interrupt the ongoing call with handset 102 via line A.
Relay 106 thus stays in its second state and, when circuit 113 makes transistor 10 conductive an instant after contact 9.2 is closed,handset 2 is thus connected to line B. The user of apparatus 101 may then cut in on the ongoing call on line B to request that the line be freed, or may place handset 2 back on its support.
In this case, as in case 3 above, the output llc of voltage detector circuit 11 and thus the input 113c of circuit 113 go high in response to the closing of contact 9.1.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is low because handset 102 is not in use, circuit 113 delivers a current pulse to the coil 106a of relay 106 which thus takes its first state.
As in case 1 above, circuit 113 also makes transistor 10 conductive a short instant after contact 9.2 is closed, and indirectly connects its input 113d to its output 113k.
Handset 2 is thus connected to line A via speech circuit 5.
If line A is free, the user may then select the number to be called. If however, line A is already engaged by a call with telephone 15, the user of apparatus 101 may cut in on this call to request that the line be freed, or may place handset 2 back on its support.
If, at the moment when the input 113c of circuit 113 goes high, the input 113j of circuit 113 is high because the handset 102 is already in use, the circuit 113 delivers ~pulse to the coil 106a of relay 106 in order not to interrupt the ongoing call with handset 102 via line A.
Relay 106 thus stays in its second state and, when circuit 113 makes transistor 10 conductive an instant after contact 9.2 is closed,handset 2 is thus connected to line B. The user of apparatus 101 may then cut in on the ongoing call on line B to request that the line be freed, or may place handset 2 back on its support.
6. The user of apparatus lOl lifts up the handset 102 whiIe relay 106 is in its second state and line A is already engaged by a call with the telephone 15.
; ~ In this case, as in case 4 above, the output lllc of voltage detector ~circuit 111 and the input 113i of circuit 113 go high in ;response to the closing of contact ~, 109.1. : , If, at the moment when the input 113i of circuit 113 goes high, the input 113e of circuit 113 is low because handset 2 is not in use, circuit 113 delivers a current pulse to the coil 106a of relay 106 which thus takes its first state.
As in case 2 above, circuit 113 also makes transistor 110 conductive a short instant after contact 109.2 is closed, and indirectly connects its input 113d to its output 113k. Handset 102 is thus connected to line B
via speech circuit 105.
If line B is free, the user may then select the .
ffumber to be called. If, however, line B is already engaged by a call with telephone 16, the user of apparatus 101 may cut in on this call to request that the line be freed, or may place handset 102 back on its support.
If, at the moment when the input 113i of circuit 113 goes high, the input 113e of circuit 113 is high because handset 2 is already in use, circuit delivers no pulse to the coil 106a of relay 106, in order not to interrupt ~ - 24 -the ongoing call with handset 2 via line B. Relay 106 stays in its second state and when circuit 113 makes the transistor 110 conductive an instant after contact 109.2 is closed, handset 102 is connected to line A. The user of 5 apparatus 101 may then cut in on the ongoing call on line A to request that the line be freed, or may place handset 102 back on its support.
It is clear that, like the control circuit 13 of apparatus 1 of Fig. 1, the control circuit 113 of 10 apparatus 101 of Fig. 4 may be arranged in such a manner that transistor 10 or transistor 110 is not made conductive after a user lifts up handset 2 or handset 102 to make a call while both lines A and B are engaged. In such a case, control circuit 113, like circuit 13, 15 advantageously includes means producing an optical and/or acoustic signal to alert the user that he cannot use apparatus lQ1 to make a call.
It is also clear that control circuit 13 may be made differently to what has been described, or that it could even be replaced by a microcomputer programmed to perform the same functions. The same applies to circuit 113.
It is furthermore clear that the present invention is not limited to the embodiments of the telephone apparatus which have been just described.
Thus, for example, the present invention applies also to a telephone apparatus adapted to be connected to more that two telephone lines and/or that has more than two independent handsets.
This invention applies also to cases similar to what is described with reference to Figs. 1 and 2 but where the telephone apparatus does not include a base, all of the components of this apparatus being assembled in the handset casing. In such cases, contacts such as 9.1 and 9.2 of Fig. 1 may for example be actuated by a push button or by a slidably-mounted button.
~ ' ' . ~ !
^ - 25 ~ 3~6 ~
The present invention also applies to the case where the base of the telephone apparatus itself forms or replaces one of the two handsets, as in the apparatus described in U5 patent 4'817'138.
.--, ~ , , .
; ~ In this case, as in case 4 above, the output lllc of voltage detector ~circuit 111 and the input 113i of circuit 113 go high in ;response to the closing of contact ~, 109.1. : , If, at the moment when the input 113i of circuit 113 goes high, the input 113e of circuit 113 is low because handset 2 is not in use, circuit 113 delivers a current pulse to the coil 106a of relay 106 which thus takes its first state.
As in case 2 above, circuit 113 also makes transistor 110 conductive a short instant after contact 109.2 is closed, and indirectly connects its input 113d to its output 113k. Handset 102 is thus connected to line B
via speech circuit 105.
If line B is free, the user may then select the .
ffumber to be called. If, however, line B is already engaged by a call with telephone 16, the user of apparatus 101 may cut in on this call to request that the line be freed, or may place handset 102 back on its support.
If, at the moment when the input 113i of circuit 113 goes high, the input 113e of circuit 113 is high because handset 2 is already in use, circuit delivers no pulse to the coil 106a of relay 106, in order not to interrupt ~ - 24 -the ongoing call with handset 2 via line B. Relay 106 stays in its second state and when circuit 113 makes the transistor 110 conductive an instant after contact 109.2 is closed, handset 102 is connected to line A. The user of 5 apparatus 101 may then cut in on the ongoing call on line A to request that the line be freed, or may place handset 102 back on its support.
It is clear that, like the control circuit 13 of apparatus 1 of Fig. 1, the control circuit 113 of 10 apparatus 101 of Fig. 4 may be arranged in such a manner that transistor 10 or transistor 110 is not made conductive after a user lifts up handset 2 or handset 102 to make a call while both lines A and B are engaged. In such a case, control circuit 113, like circuit 13, 15 advantageously includes means producing an optical and/or acoustic signal to alert the user that he cannot use apparatus lQ1 to make a call.
It is also clear that control circuit 13 may be made differently to what has been described, or that it could even be replaced by a microcomputer programmed to perform the same functions. The same applies to circuit 113.
It is furthermore clear that the present invention is not limited to the embodiments of the telephone apparatus which have been just described.
Thus, for example, the present invention applies also to a telephone apparatus adapted to be connected to more that two telephone lines and/or that has more than two independent handsets.
This invention applies also to cases similar to what is described with reference to Figs. 1 and 2 but where the telephone apparatus does not include a base, all of the components of this apparatus being assembled in the handset casing. In such cases, contacts such as 9.1 and 9.2 of Fig. 1 may for example be actuated by a push button or by a slidably-mounted button.
~ ' ' . ~ !
^ - 25 ~ 3~6 ~
The present invention also applies to the case where the base of the telephone apparatus itself forms or replaces one of the two handsets, as in the apparatus described in U5 patent 4'817'138.
.--, ~ , , .
Claims
1. A telephone apparatus adapted to be connected to a plurality of telephone lines each able to have a free state and an engaged state and each able to transmit a call signal, including an electro-acoustic unit compri-sing a microphone and an earphone and switching means responsive to any one of said call signals to selective-ly connect said electro-acoustic unit to the line that transmits this call signal, further including means for producing a signal indicative of use of said electro-acoustic unit and means for producing an engaged signal in response to the engaged state of the line that is connected to said electro-acoustic unit, and said switching means being further responsive to said signal indicative of use and to said engaged signal to connect said electro-acoustic unit to another of said lines.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8908236 | 1989-06-19 | ||
| FR8908236A FR2648653B1 (en) | 1989-06-19 | 1989-06-19 | TELEPHONE DEVICE FOR CONNECTION TO SEVERAL TELEPHONE LINES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2019166A1 true CA2019166A1 (en) | 1990-12-19 |
Family
ID=9382966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002019166A Abandoned CA2019166A1 (en) | 1989-06-19 | 1990-06-18 | Telephone apparatus adapted to be connected to several telephone lines |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0403923A1 (en) |
| JP (1) | JPH0332139A (en) |
| AU (1) | AU5717790A (en) |
| CA (1) | CA2019166A1 (en) |
| DD (1) | DD295293A5 (en) |
| FR (1) | FR2648653B1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2698230A1 (en) * | 1992-11-18 | 1994-05-20 | Swatch Ag | Telephone terminal serving number of switchable lines - has switching mechanism operated by current to produce active state for changing over between two sets of lines |
| US5408525A (en) * | 1994-05-24 | 1995-04-18 | General Instrument Corporation Of Delaware | Diverter interface between two telecommunication lines and a station set |
| US6586086B1 (en) | 1999-09-13 | 2003-07-01 | Tdk Corporation | Magnetic recording medium and making method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2914337C2 (en) * | 1979-04-09 | 1985-09-12 | Telefonbau Und Normalzeit Gmbh, 6000 Frankfurt | Circuit arrangement for a telephone set that can be connected to several connecting lines |
| SG36707G (en) * | 1987-04-14 | 1995-09-18 | Ebauchesfabrik Eta Ag | Telephone set |
| FR2622380B1 (en) * | 1987-10-22 | 1990-02-09 | Cousin Didier | TELEPHONE LINE DISTRIBUTION SYSTEM FOR A SINGLE TELEPHONE SET |
-
1989
- 1989-06-19 FR FR8908236A patent/FR2648653B1/en not_active Expired - Lifetime
-
1990
- 1990-06-12 EP EP90111047A patent/EP0403923A1/en not_active Withdrawn
- 1990-06-13 DD DD90341632A patent/DD295293A5/en not_active IP Right Cessation
- 1990-06-18 CA CA002019166A patent/CA2019166A1/en not_active Abandoned
- 1990-06-18 AU AU57177/90A patent/AU5717790A/en not_active Abandoned
- 1990-06-19 JP JP2158889A patent/JPH0332139A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0403923A1 (en) | 1990-12-27 |
| FR2648653B1 (en) | 1991-09-13 |
| JPH0332139A (en) | 1991-02-12 |
| AU5717790A (en) | 1990-12-20 |
| FR2648653A1 (en) | 1990-12-21 |
| DD295293A5 (en) | 1991-10-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3904834A (en) | Handsfree loudspeaking key telephone set and a switching circuit for use in a microphone and loudspeaker equipped key telephone | |
| US5481596A (en) | Auxiliary baseband telephone interface for an answering machine | |
| US4408102A (en) | Two-wire exchange telephone system | |
| US4059732A (en) | Centralized telephone answering apparatus with remote accessing | |
| US4472602A (en) | Telephone set with transducer/ringer | |
| US4588864A (en) | Small key telephone system | |
| CA2019166A1 (en) | Telephone apparatus adapted to be connected to several telephone lines | |
| JPH0131745B2 (en) | ||
| US4508938A (en) | Push-button dial for a telephone | |
| US4283603A (en) | On-hook/off-hook status check circuit | |
| CA1160783A (en) | Electronic lock, switching, and hold devices for telephones | |
| US4868847A (en) | Telephone intercom device | |
| EP0235883A1 (en) | Telephone intercom device | |
| JP2637085B2 (en) | Telephone system | |
| JPS61103356A (en) | Key telephone set | |
| JPH02254844A (en) | Control system for multiple gate door system with television set | |
| JP2669828B2 (en) | Telephone system PB signal receiver | |
| JPH0349492Y2 (en) | ||
| JP2637083B2 (en) | Main equipment of telephone system | |
| JPH0771160B2 (en) | Telephone switching equipment | |
| JPS622497B2 (en) | ||
| JPH0544239B2 (en) | ||
| JPH03145849A (en) | Telephone set | |
| JPH0235854A (en) | Telephone set | |
| JPH0445024B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |