CA2248488A1 - Integrated wallbox - Google Patents
Integrated wallbox Download PDFInfo
- Publication number
- CA2248488A1 CA2248488A1 CA 2248488 CA2248488A CA2248488A1 CA 2248488 A1 CA2248488 A1 CA 2248488A1 CA 2248488 CA2248488 CA 2248488 CA 2248488 A CA2248488 A CA 2248488A CA 2248488 A1 CA2248488 A1 CA 2248488A1
- Authority
- CA
- Canada
- Prior art keywords
- output
- connection
- cable
- network interface
- interface device
- 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
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
- H04B3/56—Circuits for coupling, blocking, or by-passing of signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5429—Applications for powerline communications
- H04B2203/5437—Wired telephone
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5429—Applications for powerline communications
- H04B2203/5445—Local network
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B2203/00—Indexing scheme relating to line transmission systems
- H04B2203/54—Aspects of powerline communications not already covered by H04B3/54 and its subgroups
- H04B2203/5462—Systems for power line communications
- H04B2203/5491—Systems for power line communications using filtering and bypassing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
An integrated wallbox is provided for protecting devices connected to a cable network from hazards which may arise on the network such as overcurrents, overvoltages and low frequency signals. A fuse is provided for overcurrent protection, and an inductor and a sideactor are provided for overvoltage protection, a DC blocking capacitor is provided to block DC and low frequency AC power signals. These components are all integrated on a printed circuit board within a housing to minimize connection losses.
Description
INTEGRATED WALLBOX
Field of the Invention The invention relates to protection devices for use at the interface of a cable network with a cable inside a subscriber's home for protecting equipment inside the subscriber's home from hazards which may exist on the cable network.
Background of the Invention Telephone service providers are obligated by law to provide networks and services which have a very high quality, are up and running a large percentage of the time, and have a minimum possible impact to customer equipment. This is because a telephone is considered a potentially important life-line in the case of an emergency. In contrast, in the past cable service providers were not concerned with the quality of the connections they provided from the cable network to a subscriber's home because these connections were only used to provide entertainment programming. For the occasional case when customer equipment was damaged due to its connection to the cable network, cable service providers typically were obligated to pay for the replacement or repair of the equipment.
The evolution of new broadband services such as telecom applications over cable has resulted in the requirement for much higher quality in cable connections. The integrity of a broadband network for telecom applications must be much higher than that for a typical cable company network.
With particular regard to minimizing the potential damage to customer equipment connected to the network, there are several hazards which may exist from time to time. These include lightning and voltage transients, current surges, and DC drift to name a few. It is possible to combine existing equipment for protecting against each of these hazards, but such a combination would result in losses which are unacceptably high.
There may also be AC power transmitted down the cable which needs to be blocked from getting to the customer's equipment.
Summary of the Invention It is an object of the invention to obviate or mitigate one or more of the above identified disadvantages.
According to a broad aspect, the invention provides a network interface device for connecting a first coax cable susceptible to various electronic hazards to a second coax cable for connection to a component requiring protection from these hazards, the cable connector comprising: a metal housing having a ground terminal; an input coax connector formed in the housing for connection to the first cable, the input coax connector having an input centre conductor connection and an input ground sheath connection connected to the ground terminal through the metal housing; a first output coax connector formed in the housing for connection to the second cable, the first output coax connector having a first output centre conductor connection and a first output ground sheath connection connected to the ground terminal through the metal housing; the metal housing enclosing: a printed circuit board, a centre conductor fuse connected between the input centre conductor connection and a first point which when blown will not provide a conductive path for either RF or power, a DC blocking capacitor having a capacitance C connected between the first point and the first output centre conductor connection; an inductor having an inductance L and a sidactor having a hold voltage V connected together in series between the first point and the ground terminal; wherein the fuse, DC blocking capacitor, inductor and sidactor are connected together on the printed circuit board; wherein C is selected to block low frequency signals and to pass high frequency signals; the sidactor is selected to operate as a high voltage surge protector/arrestor/absorber to clamp high voltage surges to the hold voltage V; the fuse is selected to have a blow characteristic such that it will blow if excessive currents exist; and L is selected to allow RF frequencies to pass through the network interface device unaffected by the presence of the sideactor.
Brief Description of the Drawings Preferred embodiments of the invention will now be described with reference to the attached drawings in which:
Figure 1 is an illustration of a context within which an integrated wallbox according to an embodiment of the invention might be used;
Figure 2 is a pictorial representation of the external housing and connections for the integrated wallbox of the invention; and Figure 3 is a schematic of circuitry mounted within the housing of Figure 2.
Detailed Description of the Preferred Embodiments Referring firstly to Figure 1, an IWB (integrated wallbox) 10 according to an embodiment of the invention is shown installed on an exterior wall of a subscriber's home 12.
The cable network 13 is connected to the IWB 10 outside the home through a drop cable 14, and cables leading from the IWB
Field of the Invention The invention relates to protection devices for use at the interface of a cable network with a cable inside a subscriber's home for protecting equipment inside the subscriber's home from hazards which may exist on the cable network.
Background of the Invention Telephone service providers are obligated by law to provide networks and services which have a very high quality, are up and running a large percentage of the time, and have a minimum possible impact to customer equipment. This is because a telephone is considered a potentially important life-line in the case of an emergency. In contrast, in the past cable service providers were not concerned with the quality of the connections they provided from the cable network to a subscriber's home because these connections were only used to provide entertainment programming. For the occasional case when customer equipment was damaged due to its connection to the cable network, cable service providers typically were obligated to pay for the replacement or repair of the equipment.
The evolution of new broadband services such as telecom applications over cable has resulted in the requirement for much higher quality in cable connections. The integrity of a broadband network for telecom applications must be much higher than that for a typical cable company network.
With particular regard to minimizing the potential damage to customer equipment connected to the network, there are several hazards which may exist from time to time. These include lightning and voltage transients, current surges, and DC drift to name a few. It is possible to combine existing equipment for protecting against each of these hazards, but such a combination would result in losses which are unacceptably high.
There may also be AC power transmitted down the cable which needs to be blocked from getting to the customer's equipment.
Summary of the Invention It is an object of the invention to obviate or mitigate one or more of the above identified disadvantages.
According to a broad aspect, the invention provides a network interface device for connecting a first coax cable susceptible to various electronic hazards to a second coax cable for connection to a component requiring protection from these hazards, the cable connector comprising: a metal housing having a ground terminal; an input coax connector formed in the housing for connection to the first cable, the input coax connector having an input centre conductor connection and an input ground sheath connection connected to the ground terminal through the metal housing; a first output coax connector formed in the housing for connection to the second cable, the first output coax connector having a first output centre conductor connection and a first output ground sheath connection connected to the ground terminal through the metal housing; the metal housing enclosing: a printed circuit board, a centre conductor fuse connected between the input centre conductor connection and a first point which when blown will not provide a conductive path for either RF or power, a DC blocking capacitor having a capacitance C connected between the first point and the first output centre conductor connection; an inductor having an inductance L and a sidactor having a hold voltage V connected together in series between the first point and the ground terminal; wherein the fuse, DC blocking capacitor, inductor and sidactor are connected together on the printed circuit board; wherein C is selected to block low frequency signals and to pass high frequency signals; the sidactor is selected to operate as a high voltage surge protector/arrestor/absorber to clamp high voltage surges to the hold voltage V; the fuse is selected to have a blow characteristic such that it will blow if excessive currents exist; and L is selected to allow RF frequencies to pass through the network interface device unaffected by the presence of the sideactor.
Brief Description of the Drawings Preferred embodiments of the invention will now be described with reference to the attached drawings in which:
Figure 1 is an illustration of a context within which an integrated wallbox according to an embodiment of the invention might be used;
Figure 2 is a pictorial representation of the external housing and connections for the integrated wallbox of the invention; and Figure 3 is a schematic of circuitry mounted within the housing of Figure 2.
Detailed Description of the Preferred Embodiments Referring firstly to Figure 1, an IWB (integrated wallbox) 10 according to an embodiment of the invention is shown installed on an exterior wall of a subscriber's home 12.
The cable network 13 is connected to the IWB 10 outside the home through a drop cable 14, and cables leading from the IWB
feed inside the home for connection to the customer's equipment such as their television and computer for example.
A preferred embodiment of the IWB will now be described with reference to Figures 2 and 3. The external features of the IWB are shown in Figure 2, and include an hermetically sealed nickel plated corrosion resistant conductive metal housing 16, an input coax connector 18 for connection to the drop cable, two output coax connectors 20,22 for connection to equipment inside the customer's home, a ground terminal 24, and four mounting pads 26. The input coax connector 18 and the two output coax connectors are preferably F-plug type connectors. Each F-plug connector 18,20,22 has an outer ground sheath connection and a centre conductor connection for providing connections to the ground sheath and centre conductor of a coax cable respectively. The outer ground sheath connections are also connected through the metal housing 16 to the ground terminal 24.
The circuitry mounted inside the housing of Figure 2 is shown schematically in Figure 3. The centre conductor connection of the input coax connector 18 is connected to one end of a fuse 30. The other end of the fuse is connected both to a DC blocking capacitor 32 and to one end of an inductor 34.
The DC blocking capacitor 32 is connected to one end of a first RF coil 36 forming the single ended input side of a splitter generally indicated by 38, the other end of the coil 36 being connected to a ground connection 42. The other end of inductor 34 is connected through a sidactor 40 to the ground connection 42. The two centre conductor connections of the output coax connectors 20, 22 are respectively connected to opposite ends of a second RF coil 44 forming the double ended output part of the splitter 38. The centre tap of the second RF coil 44 also has a connection to the ground connection 42.
The ground connection 42 may for example be the conductive housing with the result that one end of the sidactor 40, one end of the first RF coil 36, the centre tap of the second RF coil 44, and the ground sheath connections of the 5 coax connectors are connected to the ground terminal 24 (see fig. 2) through the conductive housing.
The ground terminal 24 is preferably connected through a #6 AWG wire. This wire is required to provide a ground path from the IWB to the earth ground when in use.
Generally, the #6 ground wire is attached directly to a ground rod, or to a hydro/communications mast attached to the ground rod.
The DC blocking capacitor 32 provides low frequency voltage protection bi-directionally between the network and the customer. The function of the DC blocking capacitor 32 is to provide low frequency blocking, and in particular to block any power transmitted down the drop cable, for example a 60 Hz power signal, while allowing RF frequencies between 5 - 1000 MHZ to pass to the splitter 38. The DC blocking capacitor 32 and the inductor 34 together combine to form an LC circuit with the required bandpass characteristics. The DC blocking capacitor 32 allows for the presence of broadband power on the network side of the drop cable without impacting the customer's equipment.
The sidactor 40 limits voltage surges to a maximum value, for example 160 volts. The sidactor 40 is preferably an avalanche diode with a 160V breakdown voltage. An incoming signal having a voltage greater than 160 volts will have its voltage reduced to 160 volts by the sidactor 40. The inductor 34 is in series with the sidactor. The function of the inductor is to allow RF frequencies between 5 and 1000 MHZ to pass to/from the splitter, unaffected by the presence of the sidactor.
The fuse 30 limits the amount of current to the IWB.
The fuse 30 is used as a failsafe device to stop excessive current from ever being transmitted through the IWB to the customer's equipment. The fuse will also operate (blow) if the sidactor circuitry 34,40 goes into self sacrifice mode caused by unwanted excessive power dissipation.
The splitter 38 provides two RF bi-directional circuits. Both circuits are engineered to bandpass frequencies in the 5-1000 MHZ range.
In normal operation, 60V-90V, and RF signals are sent down the drop cable 14 through the IWB 10 to the customer's equipment, and similar signals are sent from the customer's equipment through the IWB and the drop cable to the cable network.
Any AC power sent down the drop is blocked by the DC
blocking capacitor 32. Any voltages above the maximum value of the sidactor 40 (preferably 160V) will be bled off through the sideactor 40 and the inductor 34. Any incoming current greater than the maximum passable by the fuse 30 will result in the fuse blowing, and the IWB 10 becoming functionality disconnected from the drop cable 14.
When a voltage surge occurs, the voltage is passed by the fuse 30, and ramps up on the inductor 34. The sidactor 40 then holds the voltage at a maximum of 160V, and it is this 160 volt maximum which is presented to the blocking capacitator 32.
Surges typically result in low frequency signals which are blocked by the DC blocking capacitor 32 and passed down through the sideactor circuitry 34,40.
The integration of all of the components of the IWB
is done on a custom designed printed circuit board. This minimizes the losses in the connections between components.
A preferred embodiment of the IWB will now be described with reference to Figures 2 and 3. The external features of the IWB are shown in Figure 2, and include an hermetically sealed nickel plated corrosion resistant conductive metal housing 16, an input coax connector 18 for connection to the drop cable, two output coax connectors 20,22 for connection to equipment inside the customer's home, a ground terminal 24, and four mounting pads 26. The input coax connector 18 and the two output coax connectors are preferably F-plug type connectors. Each F-plug connector 18,20,22 has an outer ground sheath connection and a centre conductor connection for providing connections to the ground sheath and centre conductor of a coax cable respectively. The outer ground sheath connections are also connected through the metal housing 16 to the ground terminal 24.
The circuitry mounted inside the housing of Figure 2 is shown schematically in Figure 3. The centre conductor connection of the input coax connector 18 is connected to one end of a fuse 30. The other end of the fuse is connected both to a DC blocking capacitor 32 and to one end of an inductor 34.
The DC blocking capacitor 32 is connected to one end of a first RF coil 36 forming the single ended input side of a splitter generally indicated by 38, the other end of the coil 36 being connected to a ground connection 42. The other end of inductor 34 is connected through a sidactor 40 to the ground connection 42. The two centre conductor connections of the output coax connectors 20, 22 are respectively connected to opposite ends of a second RF coil 44 forming the double ended output part of the splitter 38. The centre tap of the second RF coil 44 also has a connection to the ground connection 42.
The ground connection 42 may for example be the conductive housing with the result that one end of the sidactor 40, one end of the first RF coil 36, the centre tap of the second RF coil 44, and the ground sheath connections of the 5 coax connectors are connected to the ground terminal 24 (see fig. 2) through the conductive housing.
The ground terminal 24 is preferably connected through a #6 AWG wire. This wire is required to provide a ground path from the IWB to the earth ground when in use.
Generally, the #6 ground wire is attached directly to a ground rod, or to a hydro/communications mast attached to the ground rod.
The DC blocking capacitor 32 provides low frequency voltage protection bi-directionally between the network and the customer. The function of the DC blocking capacitor 32 is to provide low frequency blocking, and in particular to block any power transmitted down the drop cable, for example a 60 Hz power signal, while allowing RF frequencies between 5 - 1000 MHZ to pass to the splitter 38. The DC blocking capacitor 32 and the inductor 34 together combine to form an LC circuit with the required bandpass characteristics. The DC blocking capacitor 32 allows for the presence of broadband power on the network side of the drop cable without impacting the customer's equipment.
The sidactor 40 limits voltage surges to a maximum value, for example 160 volts. The sidactor 40 is preferably an avalanche diode with a 160V breakdown voltage. An incoming signal having a voltage greater than 160 volts will have its voltage reduced to 160 volts by the sidactor 40. The inductor 34 is in series with the sidactor. The function of the inductor is to allow RF frequencies between 5 and 1000 MHZ to pass to/from the splitter, unaffected by the presence of the sidactor.
The fuse 30 limits the amount of current to the IWB.
The fuse 30 is used as a failsafe device to stop excessive current from ever being transmitted through the IWB to the customer's equipment. The fuse will also operate (blow) if the sidactor circuitry 34,40 goes into self sacrifice mode caused by unwanted excessive power dissipation.
The splitter 38 provides two RF bi-directional circuits. Both circuits are engineered to bandpass frequencies in the 5-1000 MHZ range.
In normal operation, 60V-90V, and RF signals are sent down the drop cable 14 through the IWB 10 to the customer's equipment, and similar signals are sent from the customer's equipment through the IWB and the drop cable to the cable network.
Any AC power sent down the drop is blocked by the DC
blocking capacitor 32. Any voltages above the maximum value of the sidactor 40 (preferably 160V) will be bled off through the sideactor 40 and the inductor 34. Any incoming current greater than the maximum passable by the fuse 30 will result in the fuse blowing, and the IWB 10 becoming functionality disconnected from the drop cable 14.
When a voltage surge occurs, the voltage is passed by the fuse 30, and ramps up on the inductor 34. The sidactor 40 then holds the voltage at a maximum of 160V, and it is this 160 volt maximum which is presented to the blocking capacitator 32.
Surges typically result in low frequency signals which are blocked by the DC blocking capacitor 32 and passed down through the sideactor circuitry 34,40.
The integration of all of the components of the IWB
is done on a custom designed printed circuit board. This minimizes the losses in the connections between components.
Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.
In the illustrated embodiment, the wallbox is shown mounted external to a subscriber's home. Of course it may also be mounted in an interior location.
In another preferred embodiment of the invention the IWB circuitry further includes a power connection 50 (shown in dotted lines in Figure 3) before the DC blocking capacitor to allow the receipt of power down the drop cable 14, for example to power life line services such as telephony.
While in the illustrated embodiment a splitter function is provided in addition to the various forms of protection, an IWB may also be designed without the splitter function.
In the above, an example of a sidactor has been given consisting of an avalanche diode with a 160V breakdown voltage.
Of course any sidactor component may be used which is capable of presenting a high impedance to the high side of the sidactor (the side being monitored) while the voltage being monitored is below a defined clamping voltage, and which is capable of quickly switching to a conducting mode when the voltage exceeds the clamping voltage.
In the illustrated embodiment, the wallbox is shown mounted external to a subscriber's home. Of course it may also be mounted in an interior location.
In another preferred embodiment of the invention the IWB circuitry further includes a power connection 50 (shown in dotted lines in Figure 3) before the DC blocking capacitor to allow the receipt of power down the drop cable 14, for example to power life line services such as telephony.
While in the illustrated embodiment a splitter function is provided in addition to the various forms of protection, an IWB may also be designed without the splitter function.
In the above, an example of a sidactor has been given consisting of an avalanche diode with a 160V breakdown voltage.
Of course any sidactor component may be used which is capable of presenting a high impedance to the high side of the sidactor (the side being monitored) while the voltage being monitored is below a defined clamping voltage, and which is capable of quickly switching to a conducting mode when the voltage exceeds the clamping voltage.
Claims (7)
1. A network interface device for connecting a first coax cable susceptible to various electronic hazards to a second coax cable for connection to a component requiring protection from these hazards, the cable connector comprising:
a metal housing having a ground terminal;
an input coax connector formed in the housing for connection to the first cable, the input coax connector having an input centre conductor connection and an input ground sheath connection connected to the ground terminal through the metal housing;
a first output coax connector formed in the housing for connection to the second cable, the first output coax connector having a first output centre conductor connection and a first output ground sheath connection connected to the ground terminal through the metal housing;
the metal housing enclosing:
a printed circuit board, a centre conductor fuse connected between the input centre conductor connection and a first point which when blown will not provide a conductive path for either RF or power;
a DC blocking capacitor having a capacitance C connected between the first point and the first output centre conductor connection;
an inductor having an inductance L and a sidactor having a hold voltage V connected together in series between the first point and the ground terminal;
wherein the fuse, DC blocking capacitor, inductor and sidactor are connected together on the printed circuit board;
wherein C is selected to block low frequency signals and to pass high frequency signals;
the sidactor is selected to operate as a high voltage surge protector/arrestor/absorber to clamp high voltage surges to the hold voltage V;
the fuse is selected to have a blow characteristic such that it will blow if excessive currents exist; and L is selected to allow RF frequencies to pass through the network interface device unaffected by the presence of the sideactor.
a metal housing having a ground terminal;
an input coax connector formed in the housing for connection to the first cable, the input coax connector having an input centre conductor connection and an input ground sheath connection connected to the ground terminal through the metal housing;
a first output coax connector formed in the housing for connection to the second cable, the first output coax connector having a first output centre conductor connection and a first output ground sheath connection connected to the ground terminal through the metal housing;
the metal housing enclosing:
a printed circuit board, a centre conductor fuse connected between the input centre conductor connection and a first point which when blown will not provide a conductive path for either RF or power;
a DC blocking capacitor having a capacitance C connected between the first point and the first output centre conductor connection;
an inductor having an inductance L and a sidactor having a hold voltage V connected together in series between the first point and the ground terminal;
wherein the fuse, DC blocking capacitor, inductor and sidactor are connected together on the printed circuit board;
wherein C is selected to block low frequency signals and to pass high frequency signals;
the sidactor is selected to operate as a high voltage surge protector/arrestor/absorber to clamp high voltage surges to the hold voltage V;
the fuse is selected to have a blow characteristic such that it will blow if excessive currents exist; and L is selected to allow RF frequencies to pass through the network interface device unaffected by the presence of the sideactor.
2. A network interface device according to claim 1 wherein the fuse is selected to have the fusing characteristics of a 30 AWG copper conductor.
3. A network interface device according to claim 2 wherein the DC blocking capacitor and inductor are selected to realize an LC circuit which passes RF frequencies in the range of 5Mhz to 1000Mhz between the input connector and the first output connector.
4. A network interface device according to claim 3 wherein the sideactor hold voltage V is 160V.
5. A network interface device according to claim 1 further comprising a second output coax connector formed in the housing and having a second output inner conductor connection and a second output ground sheath connection connected to the ground terminal through the metal housing, and further comprising a splitter component connected on a first side to the capacitor and on a second side to the two output coax connectors.
6. A network interface device according to claim 1 further comprising a power connector at said first point for enabling low frequency power transmitted down the first cable to be extracted without effecting RF frequencies between 5-1000 MHz.
7. A network interface device according to claim 1 wherein said metal housing is hermetically sealed, and made of nickel-plated corrosion resistant conductive metal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2248488 CA2248488A1 (en) | 1998-09-28 | 1998-09-28 | Integrated wallbox |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2248488 CA2248488A1 (en) | 1998-09-28 | 1998-09-28 | Integrated wallbox |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2248488A1 true CA2248488A1 (en) | 2000-03-28 |
Family
ID=29409961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2248488 Abandoned CA2248488A1 (en) | 1998-09-28 | 1998-09-28 | Integrated wallbox |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2248488A1 (en) |
-
1998
- 1998-09-28 CA CA 2248488 patent/CA2248488A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |