Abstract:
The NTU receiving structure ( 14 ) is further adapted to receive a demountable casing ( 15 ) for enclosing a second network termination unit ( 16 ). The fiber management unit ( 11 ) is further adapted for accommodating the outer end of a second optical fiber with a second optical connector ( 32 ). The fiber termination unit ( 10 ) further comprises a second NTU connection unit ( 23 ) for positioning the second optical connector ( 32 ) in a position suitable for connecting the second optical connector ( 32 ) to a connector part of the second network termination unit ( 16 ) when the demountable casing ( 15 ) with the second network termination unit ( 16 ) is received in the NTU receiving structure ( 14 ).

Description:
FIELD OF THE INVENTION 
     This invention relates to a fiber termination unit (FTU) for connecting an optical connector at an outer end of an optical fiber to a network termination unit (NTU), the fiber termination unit comprising a fiber management unit with an NTU connection unit and an NTU receiving structure. The fiber management unit is provided for accommodating the outer end of the optical fiber. The NTU connection unit is provided for positioning the optical connector in a position suitable for connecting the optical connector to a connector part of the network termination unit. The NTU receiving structure is adapted to receive the network termination unit in such a way that, when the network termination unit is installed in the NTU receiving structure, the connector part of the network termination unit is positioned opposite to the NTU connection unit in order to enable connecting the optical connector to the connector part of the network termination unit. 
     This invention further relates to a TV receiver and a patch cord for use with such a fiber termination unit. 
     BACKGROUND OF THE INVENTION 
     Such fiber termination units are commonly installed in homes as an end station of an optical fiber network. Optical fiber networks are constructed to make it possible to transport high quantities of data at high speeds and are, e.g., used for offering Internet access, telephony and/or radio and TV services. Originally, optical fibers were mainly used for transporting data between a central main station and distribution stations in the neighborhoods. In the distribution stations, optical signals are converted to electrical signals (and vice versa) and forwarded to users in homes and/or offices. Installation and configuration of the equipment providing this conversion and connecting the equipment to the optical and electrical cables is done by specialized engineers who have been trained for this. 
     In recent years it has become increasingly usual to bring the optical fibers all the way to the home or office (FttH—Fiber to the Home). A fiber termination unit (FTU) as described above may be attached to the wall, close to where one or more optical fibers enter the home or are planned to enter the home. The optical fiber is then accommodated in the fiber termination unit. The user&#39;s telephone, PC, TV or radio cannot be connected to the fiber termination unit directly. If a user wants to use the optical fiber network for a specific data service, a dedicated network termination unit is to be connected to the optical fiber in the fiber termination unit. Different network termination units are used to facilitate for different services. 
     In a FTU there are means for supporting the incoming ground cable containing the incoming optical fibers. Furthermore the FTU accommodates for a number of optical connectors with fiber pigtails. The incoming optical fibers are to be connected to these fiber pigtails. This requires a trained technician or installer with special skills and equipment, since the fibers are very fragile and alignment accuracy is very strict. The most commonly used technique for connecting the fibers is by fusion splicing. The overlength of the optical fiber is stored in a means for fiber management, which is a subpart of the FTU. The optical connector(s) are placed in such a way that they can connect to a NTU. 
     Each time a user wants to subscribe to a new service, an engineer may be needed for installing a new network termination unit. Some of these problems have already been solved by previous Genexis inventions for easing the connection of the optical fibers to the fiber and/or network termination units. A currently available fiber termination unit is used in Genexis&#39; CORE product line. The CORE Advanced uses a universal fiber termination unit with two interfaces for connecting a respective incoming optical fiber to a network termination unit. It allows connecting the fiber termination unit to, e.g., a first network termination unit providing a data connection to the Internet and a second network termination unit for receiving media broadcasts (e.g. TV or radio). It is an advantage of this fiber termination unit that it is based on an open interface. The so-called universal fiber termination unit (UFTU) can be combined with network termination units of different network operators or service providers. When a user decides to subscribe to a new service or a different service provider, the corresponding new network termination unit will be compatible with the universal fiber termination unit and can be installed easily. It is, e.g., foreseen that in the near future there may be no need anymore for a TV receiver module for receiving broadcasted TV, making the second optical fiber available for other data services. 
     Although its flexibility is a very desirable aspect of the universal fiber termination unit, the modular aspect also leads to an important disadvantage, i.e. the size of the unit. A universal fiber termination unit on which the two network termination units can be installed has a width of about 20 cm, which might be too much for being placed unnoted in some corner of the room. 
     OBJECT OF THE INVENTION 
     It is an object of the invention to provide a fiber termination unit which is smaller than the known universal fiber termination unit, while maintaining flexibility and compatibility. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, this object is achieved by providing a fiber termination unit according to the opening paragraph, wherein the NTU receiving structure is adapted to receive a demountable casing for enclosing a second network termination unit and the fiber management unit is adapted for accommodating the outer end of a second optical fiber with a second optical connector at its outer end. The fiber termination unit further comprises a second NTU connection unit for positioning the second optical connector in a position suitable for connecting the second optical connector to a connector part of the second network termination unit when the demountable casing with the second network termination unit is received in the NTU receiving structure. 
     The fiber termination unit according to the invention does not only save space by adding the second NTU connection unit to the fiber management unit and allowing the second network termination unit to be connected to the same fiber management unit as the first network termination unit. The fiber termination unit according to the invention also has the flexibility and modular setup of the known universal fiber termination unit with its two universal standard interfaces. In the exemplary situation described before, when a media broadcast receiver module would become obsolete, the user can easily take the demountable casing out of the fiber termination unit, replace the media broadcast receiver module by a different network termination unit and put the casing back into the fiber termination unit. 
     It is a big advantage of the fiber termination unit according to the invention that the NTU receiving structure could be adapted to receive a standard sized first network termination unit from any available supplier of network termination units. Only the second network termination unit, which is to be placed in the demountable casing, requires special dimensions in order to fit into the casing in such a way that it can connect to the second NTU connection unit. 
     If the demountable casing and the NTU receiving structure are designed such that the whole demountable casing is positioned underneath the first network termination unit when the first network termination unit is installed, the dimensions of the fiber termination unit are comparable to the known fiber termination units that can accommodate only one network termination unit. In that way, an additional network termination unit can be used without increasing the size of the fiber termination unit. 
     When the demountable casing is placed underneath the first network termination unit, an outer surface of the demountable casing may form part of the NTU receiving structure for receiving the first network termination unit. This would enable the first network termination unit to be installed directly on top of the outer surface of the demountable casing. 
     In advantageous embodiments of the fiber termination unit according to the invention, the demountable casing and the NTU receiving structure are designed such that the demountable casing can be demounted and remounted with the first network termination unit already installed. This would make it even easier to install new or additional network termination units. 
     Optionally, the fiber management unit is demountable from the fiber termination unit. Traditionally, the fiber management unit is an integrated part of the fiber termination unit. In this embodiment of the invention, the fiber management unit is a separate subpart of the fiber termination unit. This embodiment has the advantage that the installation of the installation does not have to take place in the exact same place as where the ground cable comes into the house and where the fiber termination unit is fixed to the wall. As described above, the actual fiber installation requires special skills and equipment. The fiber installation gets easier when there is more space to perform i.e. the fiber splicing and placing (or rolling) of the fibers in the fiber management unit. 
     Instead of housing a media broadcast receiver, the demountable casing could, e.g., also comprise an optical patch cord making it possible to connect a further external module or a second fiber termination unit to the first one. With a second fiber termination unit connected to the first fiber termination unit, it may, for example, be possible to use two standard sized network termination units simultaneously. 
     According to a second aspect of the invention, a TV receiver is provided for use in a fiber termination unit as described above, the TV receiver comprising a connector part and being adapted to be received in the demountable casing, the connector part being adapted to be connected to the second optical connector. 
     According to a third aspect of the invention, an optical patch cord is provided, comprising an optical patch cord for use in a fiber termination unit as described above, the optical patch cord being adapted to be received in the demountable casing, the optical patch cable being adapted to be connected to the second optical connector. 
     These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  shows a known universal fiber termination unit, 
         FIG. 2  shows a fiber termination unit according to the invention, 
         FIG. 3  shows an exploded view of a fiber termination unit according to the invention, 
         FIG. 4   a  shows a first network termination unit being installed on the fiber termination unit, 
         FIG. 4   b  shows a first network termination unit having been installed on the fiber termination unit, 
         FIG. 5  shows a demountable casing for use in the fiber termination unit, 
         FIG. 6   a  shows a bottom view of the demountable case with a TV receiver, 
         FIG. 6   b  shows a perspective view of the demountable case with the TV receiver, 
         FIG. 7  shows the fiber termination unit according to the invention with a TV receiver being installed or demounted, and 
         FIG. 8  shows a fiber management unit for use in a fiber termination unit according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a known universal fiber termination unit  100 . The fiber termination unit of  FIG. 1  comprises two interfaces  141 ,  142  for connecting a respective incoming optical fiber to a network termination unit (not shown). It allows connecting the fiber termination unit to  100 , e.g., a first network termination unit providing a data connection to the Internet and a second network termination unit for receiving media broadcasts (e.g. TV or radio). It is an advantage of this fiber termination unit  100  that it is based on a standard interface. The so-called universal fiber termination unit (UFTU)  100  can be combined with network termination units of different service providers. When a user decides to subscribe to a new service or a different service provider, the corresponding new network termination unit will be compatible with the universal fiber termination unit  100  and can be installed easily. 
     The fiber termination unit  100  has an input for receiving a cable  103  comprising two optical fibers  101 ,  102 . The incoming optical fibers  101 ,  102  are led to a fiber management unit  111 . The fiber management unit  111  serves to roll up and contain an excess length of the optical fibers  101 ,  102 . It also accommodates splices to connect the optical fibers  101 ,  102  and fiber pigtails containing two optical connectors  151 ,  152 . The two optical connectors  151 ,  152  are installed in two respective NTU connection units  131 ,  132 . The fiber termination unit  100  is designed to be able to receive two separate network termination units at respective NTU receiving structures  141 ,  142  situated at the left and right half of the fiber termination unit  100 . When a network termination unit is installed on, e.g., the first NTU receiving structure  141 , the network termination unit is slid over the respective NTU connection unit  131  and connected to the first optical fiber  101  via the optical connector  151 . 
     The fiber termination unit  100  of  FIG. 1  can receive two standard sized network termination units. For example, one network termination unit for connecting to the Internet and one for connecting to a TV broadcast network. 
       FIG. 2  shows a fiber termination unit  10  according to the invention. This fiber termination unit  10  can also receive a first standard sized network termination unit at the NTU receiving structure  14 . The first incoming optical fiber  101  is led to fiber management unit  11 . A carrier plate  12  of the fiber management unit  11  serves to roll up and contain an excess length of the optical fiber  101 . The carrier plate  12  also accommodates a splice to connect the optical fiber  101  and a fiber pigtail containing an optical connector  31 . The optical connector  31  is installed in NTU connection unit  13 . The fiber termination unit  10  is designed to be able to receive a standard sized network termination unit at NTU receiving structure  14 . When such a network termination unit is installed, it is slid over the NTU connection unit  13  and connected to the first optical fiber  101  via the first optical connector  31 . 
     In addition to the first standardized network termination unit, the NTU receiving structure  14  according to the invention can also receive a second network termination unit in a demountable casing  15  that fits into the NTU receiving structure  14 . The NTU receiving structure  14  is designed such that the casing  15  can be demounted and remounted, even when the first network termination is already installed. The casing  15  is designed to receive a second network termination unit. When the second network termination unit, e.g. a TV broadcast receiver, is inserted into the casing  15  and the casing  15  is inserted into the NTU receiving structure  14 , the second optical fiber  102  is connected to the second network termination unit via a second optical connector (not visible in  FIG. 2 ). In this exemplary embodiment, the upper surface of the demountable casing  15  comprises a ridge  19  being part of the NTU receiving structure  14  for the first network termination unit. 
       FIG. 3  shows an exploded view of a fiber termination  10  unit according to the invention. In this view it can be seen that the fiber management unit  11  comprises a carrier plate  12  with a structure for receiving a rolled up section of the optical fibers  101 ,  102 . Both optical fibers  101 ,  102  may be received at the same side of the carrier plate  12  or a second structure for receiving a rolled up section of optical fiber  102  may be provided at the bottom side of the carrier plate  12 . The complete fiber management unit  11  can preferably be taken out of the fiber termination unit  10  to ease the installation of the optical fibers  101 ,  102 . The fiber management unit  11  comprises two NTU connection units  13 ,  23  with respective optical connectors  31 ,  32  for connecting the optical fibers  101 ,  102  to the network termination units. When the casing  15  with the second network termination unit is inserted into the NTU receiving structure  14 , the second optical fiber  102  is connected to the second optical connector  32 . 
       FIG. 4   a  shows a first network termination unit  41  being installed on the fiber termination unit  10 . The network termination unit  41  has standard dimensions and is slid over the NTU connection unit  13  to be received by the NTU receiving structure  14 .  FIG. 4   b  shows the first network termination unit  41  after installation on the fiber termination unit  10 . In this embodiment, the demountable casing  15  and the NTU receiving structure  14  are designed such that the whole demountable casing  15 , after installation, is provided underneath the installed first network termination unit  41 . Thus without increasing the size of the fiber termination unit  10 , it is made possible to add a second network termination unit in the demountable casing  15 . Although the first network termination unit  41  is already in place, it may still be possible to take out the demountable casing  15 , put a second network termination unit into the casing  15  and put the casing back into the NTU receiving structure  14 . Gripping means or some mechanical release mechanism (not shown) may be provided at the casing  15  to facilitate gripping the casing  15  when it is inserted into the NTU receiving structure  14 . 
       FIG. 5  shows a demountable casing  15  for use in the fiber termination unit  10 . The casing comprises a hole for accommodating the coupling of the optical connector  32  of the second NTU connection unit  23  to an optical input of the network termination unit to be installed in the casing  15 . In  FIG. 5 , a dust cap  52  is placed in the demountable casing to make sure the fiber tip of the optical connector  32  remains clean. Furthermore, the casing  15  comprises a connector hole  51  for coupling further cables or devices to the second network termination unit. These further cables or devices may, e.g., be coupled optically or electrically and may serve to power the second network termination unit or establish an electrical data-connection to enable, for example, control of the operation of the network termination unit. The electrical coupling to, e.g., a power source or control circuit may be separated from the power and control connections of the first network termination unit. In a special embodiment, connections to a power source and/or a control unit are provided through the first network termination unit. Because the second network termination unit is installed on top of the first network termination unit, e.g., spring contacts  69  or sliding contacts may couple both network termination units in such a way that the second network termination unit is powered and controlled via the first network termination unit. An advantage of such an architecture is that no complex additional wiring is needed to provide power and/or control lines for the second network termination unit. The casing  15  further comprises a connector hole  59  for electrical coupling between the first network termination unit and the second network termination unit. 
       FIG. 6   a  shows a bottom view of the demountable case  15  with a TV receiver  16  installed. A coax connector  17  protrudes through the connector hole  51  of the casing  15 . When the casing  15  and the TV-receiver  16  are inserted into the NTU receiving structure  14 , the TV-receiver  16  is connected to the second optical connector  32  and the coax connector  17  is available for connection to, e.g. a TV or set top box.  FIG. 6   b  shows a perspective view of the demountable case  15  with the TV receiver  16 . The fiber termination unit  10  may be designed such that the demountable case  15  with the second network termination unit  16  has to be inserted before the first network termination unit  41  is attached to the NTU receiving structure  14 . Alternatively, the demountable case  15  can also be attached when the first network termination unit is already in place. 
     Instead of a TV-receiver unit  16  or another type of network termination unit, the casing may also comprise an optical patch cord for extending the optical fiber  102  and providing an external optical connector at the connector hole  51  of the casing. This external optical connector could, e.g., be used for coupling to a second fiber termination unit  10 . 
       FIG. 7  shows the fiber termination unit  10  according to the invention with a TV receiver  16  being installed or demounted. Here the fiber termination unit  10  is shown without the first network termination unit  41  having been installed, but the casing  15  can also be slid into and out of the NTU receiving structure  14  when the first network termination unit  41  has already been installed. 
       FIG. 8  shows a fiber management unit  11  for use in a fiber termination unit  10  according to the invention. In this figure, both the first and second NTU connection units  13 ,  23  and their respective optical connectors  31 ,  32  are clearly visible. One NTU connection unit  13  is arranged on top of the carrier plate  12  and the other one  23  at the bottom. The upper part of the fiber management unit  11  has dimensions corresponding to the standard dimensions of the first network termination unit  41 . The bottom part is designed to couple the second optical connector  32  to the second network termination unit  16 . 
     It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.