The invention relates to a monitoring system for buildings and other restricted areas, utilizing the electrical network an comprised of at least one transmitting unit and at least one monitoring unit, whereat there are transmitting elements in each unit for transmission of information, such as speech or other information, over the electrical network to another unit and, correspondingly, receiving and iden¬ tification elements to recognize and repeat transmitted information and in one unit, at least, elements to form and transmit the signal of an identifiable answer-back-code to the electrical network and, in the other unit, elements to ident¬ ify the answer-back-code and to interconnect the units, where¬ at at least the monitoring unit is detachably connectable to the electrical network.

Generally, separate wiring is required in presently available monitoring and stairway phone systems. In stairway systems, a keyboard is installed on the outside at the en¬ trance door and from each key there is a wiring to a certain appartment. Especially, due to mischieves and other disturb¬ ances, the demand on monitoring phone systems is growing constantly. Therefore, ever more monitoring phone systems are installed also in old appartment houses, by the construction of which the requirements of monitoring phone systems, especially the necessary wiring, have not been taken into account. Thus there are numerous inlets to be done, which require a lot of afterward work and cleaning up. The wiring must be often done, at least partly, as surface installations. Due to the construction of presently common monitoring phone systems, the monitoring unit must be installed firmly on a certain place in every individual appartment.

Generally known different types of monitoring systems, methods are also used, in which all the equipment

is built on a certain wiring of it own. In these cases, video cameras are used, which are connected to monitors in a special monitor room by means of independent co-axial cables, and for passage control, at the doors magnetic card readers or key¬ boards are used, by means of which a door cab be opened with a magnetic card or a right code etc. These designs are complicated and difficult and, in particular, system modifications or extensions require additional installations of high price wiring. The problem by these systems is that they are strictly bound to their exact location and all modifications must be done as separate electric installations.

On basis of the above described, it may be considered clear that the present monitoring and stairway phone systems are disadvantageous in many respects. Firstly, because they are very difficult to install, more than fifty percent of the procurement price may be due to additional costs by the installation. Very often the installation is time-consuming and therefore a great nuisance to the lodgers. It is a fact that even though the installations are made with great care, yet the afterward made surface wirings remain visible.

Known from the FI patent 85086 is a monitoring phone system for staircases, especially designed for appartment houses and comprising a central unit and individual units for each appartment and where the signals between the units travel along the electrical network of the building. In said system the unit in each appartment is furnished with an answer-back- code and, accordingly, on pressing a key, an answer-back-code of a certain appartment unit starts off from the central unit to the electrical net, whereat only the appartment unit with the right answer-back-code responds to the signal coming from the central unit and alarms in that special appartment. In itself, this construction is quite useful and easy to install. In addition, it is easy and simple to make modifications in

it. Yet this system is not applicable, as such, a public monitoring and control phone system to different places, as it allows contact only between the individual units and, correspondingly, transmits the door-opening signal from the appartment unit to the central unit.

The object of this invention is to introduce a monitoring phone system, by means of which the above described disadvantages can be eliminated and by means of which differ¬ ent monitoring, passage control and other control operations can be easily carried out and the system itself is easy to install and modify along with the change of circumstances for monitoring, staircase phone control and other purposes of control.

The aim to enable above facilities by means of this inventional monitoring phone system is characterized in that the system comprises a camera equipment connected to a trans¬ mitting unit to form and transmit by means of the transmitting unit an electric picture signal along the electrical net and that in at least one monitor unit there are receiving elements to receive the picture information transmitted in electrical form along the electrical net and a display unit to show picture information in the monitoring unit.

The actual concept of the invention is that different transmitting and monitoring units are used in a way allowing connection of a camera to each transmitting unit in order to generate a picture signal in electrical form and, correspond¬ ingly, the existens of display monitors in the monitoring units, whereat the picture and speech signal of a certain transmitting unit can be transmitted over the standard electrical net in the building to the monitoring unit and seen there the moment the talking contact switches on. In the pre- ferrable embodiment of the invention, several transmitting units and several monitoring units can be utilized to open

doors or carry out other functions over whichever transmission unit. In the same way, according to another embodiment, several transmitting units can be utilized, whereat one or more monitoring units can be furnished with a control unit, by means of which it is possible to transmit a call signal to certain transmitting units by turns, to one at a time, in the same way as the transmitting unit can send a call signal to the monitoring unit, whereby it is possible, with a single monitoring unit, to look systematically and in the way wanted, at the picture displayed by different transmitting units with¬ out anyone at the transmitting unit activating the keys or in any other way transmitting a call signal to the monitoring unit. By means of the inventional design it is possible to use different gate and door monitoring systems in appartment houses, row houses or private houses and to use it at the same time also on a bigger area, for instance as a monitoring system in an industrial establishment, which can be monitored and controlled from different places on the area with only one monitoring unit connected to the electrical net and, by means of it, observing the picture transmitted by different trans¬ mitting units and also the sound, upon need. Further, to this inventional monitoring system it is possible to connect mag¬ netic card readers or for instance keys using a coded infrared transmission and, for passage control, a practical computer or a printer to record all traffic through doors etc. over the transmission units.

The invention is presented in detail in the enclosed drawings, where

Fig. 1 is a schematic general view of a monitoring phone system in an appartment house with seven appartments,

Fig. 2 is a schematic front view of a monitoring unit of a monitoring phone system,

Fig. 3 is a block diagram of the function principle of a transmitting unit in a monitoring phone system,

Fig. 4 is a block diagram of the function principle of a monitoring unit in a monitoring phone system,

Fig. 5 is a guarding and monitoring application of a monitoring phone system.

Figure 1 shows schematically a building, for instance an appartment house, with many individual appartments or other rooms. The house has a monitoring phone system as per the invention, furnished with a keyboard 2 at the entrance door l. In keyboard 2 either each key contains the information to which room or appartment Al - An the information is to be sent by each respective key, or the keys are numbered for instance according to the number of the staircase or the floor, whereby the selection is made by dialling several keys. Keyboard 2, for instance, is coupled to transmitting unit 5 which is connected to the electrical net 4 of the building by means of a feeble current cable 3. Keyboard 2 can either be an in¬ dependent keyboard or it can be firmly coupled to the trans¬ mitting unit 5. Activation of a certain key in keyboard 2 generates a signal in transmitting unit 5, whereupon, depending of the coding pattern, at pressing one single key or several keys, the transmitting unit forms a code signal in accordance with the keys activated. Each appartment Al - An, seven of which are shown in the figure, has an answer-back- code of its own. The signal code, generated by activation the respective key, is transmitted by the transmitting unit 5 to the electrical net 4. There is also a loudspeaker coupled to the keyboard 2, for talking connection from the transmitting unit to the respective receiving unit. Of course, there is a fuse board 6 in every appartment in the building, to which contact boxes 7 are connected. The monitoring unit 8 in an appartment is plugged to a contact box in the appartment, whereupon the monitoring unit is ready to function as a part of the monitoring phone system and constantly ready to receive

signals from the transmitting unit 5, in accordance with the code key set into it, and independent of in which part of the building, for instance an appartment house, said plugging to the contact box has been made, under reference number 8 a part of the monitoring unit adapter cable to the contact box 7 is shown in the figure.

When a code signal leaves the transmitting unit 5 for the electrical net 4, each monitoring unit 8 tests whether said code signal is the same as the code key programmed into it. If that is the case, the monitoring unit 8 gives alarm and if, in the monitoring unit shown in figure 2, the opening key 10 of the line is pressed, talking connection opens up bet¬ ween the loudspeaker at the keyboard 2 (fig. 1) and the moni¬ toring unit 8. The talking connection functions by the so called hands-free method, i.e. no headphones are needed. If, on account of the above described connection, the owner of the monitoring unit 8 would like to get into the caller over key¬ board 2 through the entrance door l, he presses the monitoring unit key 11 and the monitorig unit 8 will send a door opening signal over the electrical net 4 to the transmitting unit 5, from where the signal is transferred along cabel 12 (fig. 1) to the electric lock in entrance door 1. The talking connect¬ ion between monitoring unit 8 and keyboard 2 can be cut off with the switch-off key 13 in the monitoring unit in figure 2. Also an automatic connection cut-off is coupled to the moni¬ toring system, if in the monitoring phone system, after the described connection, no speech or other messages are trans¬ mitted at a certain time of adjustable length.

Figure 2 shows light emitting diodes (LEDS) under reference numbers 15, 16, 17, 18 and 19 in the monitoring unit 8. Reference number 14 shows the combination of loudspeaker and microphone (speaker microphone) in the monitoring unit 8. Reference number 20 shows for instance a 4" videophone monitor

in an appartment, from which the area around the entrance door (gate) or the person who wants to enter can be seen.

At the same time when the talking connection is switched on as described above, the transmitting unit camera 21 starts off, whereby the signal, containing the camera picture in electrical form, is connected to the talking signal and trans-mitted simultaneously with the talking signal to the monitoring unit, which has a picture monitor 20. The user of the monitoring unit can then see who is or who are in the vicinity of the transmitting unit and decide thereupon whether he will or won't open the door. The monitoring unit can also be equipped with an extra key, to generate, at first, picture connection without talking connection, which means that talk¬ ing connection can be switched on only after having noted whether the persons near the transmitter unit are people whom one is eager to speak with, in the first place.

In the following the function of the transmitting unit (central unit and door unit) and the monitoring unit (appartment unit) of the monitoring phone system is described, especially with reference to figures 3 and 4 shown as block diagrams.

CENTRAL UNIT AND DOOR UNIT FIG. 3

(The central unit and the door unit are illustrated in figure 3 as a unity, i.e. without the multi-pin signal cable between them) .

The most important components are shown in form of a block diagram in figure 3. Block 46 is a mains transformer, block 47 the regulators, which there are two of. The coupling unit 25 comprises coupling condensators, a coupling trans¬ former and many relays for coupling the central unit to the electrical net in the building, i.e. three mains relays and their three control relays plus one coupling relay. The

coupling means of transmitting/receiving is block 39, either for sound transmission or reception. The picture is trans¬ mitted when connection has got switched on and till it is switched off.

TRANSMISSION OF PICTURE CARRIER

The videphone camera 21 is at the entrance door in the door unit and records the picture of those wanting to enter. Block 30 is a control of a videphone camera 21, comprising the operation voltage supply to the camera, synchronizing pulses and signal processing. Block 37 is a picture carrier generator 95...125 kHz. The picture carrier is modulated by modulator 3 with the signal from the control unit 30 of the videophone camera 21. 3 and 10 can be substituted by a voltage controlled oscillator VCO. The coupling element 32 cuts off or allows picture carrier advancement. Blocks 33 are band-pass filters filtering off the harmonics and letting through the side bands required by the picture carrier and signal transmission.

Block 34 is a carrier summing amplifier. The modulat¬ ed picture carrier and modulated sound carrier are summed at this stage before they are taken to the band-pass filter 33 and carrier-frequency amplifier 35. The modulated picture carrier and sound carrier are amplified to a capacity suffic¬ ient enough for feeding into the electric net over stages 33, 39 and 25.

TRANSMISSION OF SOUND CARRIER

The loudspeaker microphone 51 functions as a microphone upon transmission. The coupling element 52 connects the voice signal during transmission from the loudspeaker microphone 51 further to the band-pass filter 33, which lets the sound side

band further to the sound amplifier 40. With the sound ampli¬ fier 40 the week microphone signal is amplified before modul¬ ator 42 to be strong enough. The connecting device 41 lets the sound signal in speech situtation to modulator 42. Block 38 is a sound carrier generator 95...125 kHz. In modulator 42 the sound carrier is modulated by the talking signal (38, 42 can be substituted by a voltage controlled oscillator). In the situation of sound transmission, the coupling device 43 lets the modulated sound carrier to the band-pass filter 33 and further to the carrier-frequency amplifier 34.

RECEPTION OF SOUND CARRIER

At the same time with sound carrier reception the central unit cannot send a sound carrier to an appartment unit. The modul¬ ated sound carrier with its side bands sent by the appartment unit, comes via the electrical net over stages 39, 33 of the connecting unit 25. The latter block 33a filters and amplifies the sound carrier and informs, at the same time, the logic stage 56 that the sound carrier has been identified. This stage feeds required control signals furhter to the stage of the coupling device. The coupling element 55 opens up the signal forward passage only if the central unit is receiving a carrier frequency corresponding to the sound carrier or the RESET signal. Block 54 is a sound or pulse identifier, detector, by means of which the address bits (pulses) sent by an appartment unit of the resp. staircase can be identified from the carrier at this stage when the connection is started and during manipulation.

Block 53 is the sound terminal stage, where the week sound signal is amplified to an extent sufficient for the loudspeaker microphone. Upon sound reception, the coupling element 52 lets the sound signal to the microphone 51 which

has the function of a loudspeaker. The pulse distinction stage 60 distinguishes the pulses and the door opening signal from the sound. The serial/parallel transformer 59 transforms received serial bits to parallel bits. Block 57 is an address code switch, by means of which the address of respective staircase is set. Block 58 is a reference stage, which com¬ pares the received bit pattern with the one determined by the address code switch. If they are equal, the connection can be opened. The control logic receives room information from other blocks and controls other stages itself. The outlet relay closes for ab. 10 sec. when the central unit receives a door- opening signal from an appartment unit. Thereby two closing switches of the outlet relay are closed and thereupon, for instance, 24 V 50 Hz switches on to the stairway entrance door lock or the electric counter plate.

Keyboard 48. Each appartment has its own key in the door unit at the entrance door. The numbering of keys corres¬ ponds to the numbering of the appartments in the staircase. The keyboard logic 49 is in the door unit and the central unit. It generates an address bit pattern on pressing the key and makes the central unit transmit said address bit pattern, modulated in the carrier, to the electric net in the building. The keyboard logic has for instance also an 8 x 8 key matrix. Block 50 is a 3 x 8 phase code switch. Here information is coded, to which electric net phase the said appartment is con¬ nected.

APPARTMENT UNIT FIG. 4

When the connection has been opened, the appartment unit can transmit or receive sound. Instead of speech, the appartment unit can also transmit a door-opening signal to the central unit, by means of the outlet relay in which the opening of the

entrance door can be controlled. During connection, the appartment unit can receive, constantly, picture signals and the picture of the one who wants to enter is thus visible uniterruptedly in the appartment unit videophone monitor 20 regardless of if it is being spoken or not. Otherwise, the function is in principle the same as in the central unit.

The coupling element 66 comprises coupling con- densators and a coupling transformer for coupling the appartment unit to the electrical net in the building. It does not contain any relays, as does the corresponding block of the central unit. Block 61 is the control of the entrance door lock. Block 62 is a sound carrier amplifier. Block 63 is the videphone monitor control. Block 64 is picture display. The appartment unit is connected to the electric net of the house by contact plug 65.

DOOR OPENING

When connection has got switched on, the monitoring unit (from the appartment unit) sends at pressing the door-opening key a control signal, which in the transmitting unit (central unit) or any other controllable unit makes relay to close or a control operation to function.

Figure 5 shows a design, where a monitoring phone system is utilized for passage control in a building. The figure shows a schematic illustration of a building 22 with many doors la -lc. Further, there is a fence 23 around the building with a gate Id. By each door and, accordingly, by the gate, there is a transmitting unit 5a - 5d, each of which is connected to the electric net 4, which is, among other, coupled to an illuminator 24 in the building and within the fence. The whole area and all doors can be controlled with one single monitoring unit 8 in the building, which for instance a

person staying in a certain room or moving for some reason on the area can transport along and, upon need, plug it to any outlet in the electrical net or, if staying in one place, keep it connected to the electric net.

There, by activating an alarm key in the transmitting unit, the user of the monitoring unit 8 can switch on connection and see who is at the door or the gate and open it upon need. Likewise, if working as a guard, the said person can, with suitable intervals, connect the monitoring unit 8 to each transmitting unit 5a - 5d by turns and look what the situation is like on the outside. In this embodiment, which differs from the former one, the monitoring unit 8 is furnished with an extra device similar to the transmitting unit call-code former and, accordingly, each transmission unit is furnished with an extra device similar to the call-code identifier of the moni¬ toring unit, whereat the monitoring unit and the transmitting unit can send a call-code signal to one another and, vice versa, both units can answer the call signal. Since there must not necessarily be anyone at the transmitting unit 5a - 5d to press the connection ON-key, its decoding equipment can be so coupled, that it automatically actuates picture connection at once upon receipt of a call signal but, for voice connection, the said key must be pressed either in the monitoring unit 8 or the transmitting unit 5a - 5d.

The equipment according to the invention can be used and applied in many different ways, whereat, if suitably con¬ nected, the monitoring units can be used as intercoms without any picture connection between them. Likewise, the transmit¬ ting units can, if wanted, be so coupled that talking connect¬ ion between two units is possible without picture connection . Further, it is of course possible to form combined transmit¬ ting and monitoring units, whereat they can send pictures to one another and, correspondingly, display the pictures of

either one of these units. Practically, it is then the question of a vide-ophone contact over the electrical net.

To the system different other facilities can be con¬ nected, both identification and opening patterns. For example, the transmitting unit can be furnished with a magnet card reader, by means of which the door can be opened with an opening code formed by the numbered keys of the transmitting unit keyboard. Further, it is possible to connect to or build in the transmitting unit an infrared receiver, whereby, on using a code key that transmits infrared radiation coded in a certain manner, the door or gate can be opened through the transmitting unit or other required measures carried out, which do not include any talking connection but are merely controllable by the signals from the transmitting unit and the monitoring unit to operate certain functions, as for instance to swithch on the light, open the garage door, close it etc.

Since a relatively low carrier frequency is used in the transmitting system, it is of course clear that the quality of the picture to be transmitted does not by modern technique correspond to the television picture, for instance. Likewise, the transmission of a picture my take some time, whereby it is more simple, for instance, to store the picture in a separate picture memory at 0,25 - 0,5 sec. intervals and, correspondingly, send the stored picture information to a similar memory in the receiving end, from where they are then transferred one at a time as a picture to the monitor display. This fact does not in any way distrube the use of this invent¬ ional phone system for monitoring or other surveillance and it is possible to make it still better and faster along with the constant development of camera and receiving equipment.