KR100543927B1 - Termination Device for A Telephone Line - Google Patents

Abstract

A telephone line terminal 30 for wiring based on a telephone system; A high pass filter 39 for separating a signal in a frequency band used by the high speed modem 13 for data transmission; And an impedance means 53 connected to the high pass filter 39, wherein the impedance means 53 has an impedance matching the impedance of the telephone line in the frequency band used by the high speed modem 13. terminal.

Description

Terminal Device for A Telephone Line

The present invention relates to a wireline telephone system, in particular a telephone line terminal of a PBX system with multiple telephone lines, wherein at least one telephone line comprises several telephone outlets.

For example, in many places, such as homes, hotel rooms, or offices, there are multiple telephone outlets or sockets that are connected to the same telephone line on the telephone network. A high speed modem, for example, a VDSL modem may be connected to one of the outlets to provide a high speed data service. At the same time, the other outlet of the telephone line may or may not be connected to additional communication devices such as telephones, faxes, and the like.

1 shows an interior wall of a hotel room, for example, with telephone sockets A, B, C, D connected to a telephone network via telephone line T. FIG. The telephone splitter A is connected to a service splitter. The service splitter is a coupler that brakes the signal into multiple induction signals. The splitter divides the input signal from the socket A into an output signal based on the signal frequency. The voice signal transmitted in the low frequency range is separated from the data signal transmitted in the high frequency range. The service splitter is connected to a modem and a POTS or ISDN terminal. In POTS (plane old telephone system), voice data is transmitted in the low frequency range of 0 kHz to approximately 3.4 kHz, while in ISDN, voice data is transmitted in the frequency range of 0 kHz to approximately 130 kHz. The telephone set is connected to a telephone terminal. Broadband communication devices such as personal computers or laptops are connected to modems for data transmission. The modem shown in FIG. 1 is, for example, a high speed modem such as a very high-speed digital subscriber line (VDSL) modem connected to a service splitter to provide high speed data service.

Digital subscriber lines (DSLs) provide digital connections for consumers or other end users. The digital signal transmission method allows both voice and data to be transmitted over conventional telephone lines at much higher speeds than with a normal modem. The xDSL modem may be an asymmetric digital subscriber line (ADSL), a high-bit rate digital subscriber line (HDSL), a medium bit rate digital subscriber line (MDSL), or a VDSL modem. xDSL high speed modems transmit data in the high frequency range.

2 illustrates the principle of the frequency spectrum of a signal transmitted over a conventional telephone line, in which a voice signal is transmitted in a low frequency range and a data signal is transmitted in a high frequency range. The modem sends data from the broadband communication device via the service splitter and the socket A to the telephone network (so-called upstream) and receives data from the telephone network via the socket A and the service splitter in the downstream frequency band (so-called downstream). The upstream and downstream frequency bands are separated by guard bands, which are preferably in the armature radio band to avoid interference by the armature radio.

High speed xDSL modems receive data at very high frequencies, typically higher than 1 MHz, in the downstream frequency band.

The functional relationship between the propagation velocity V of the telephone signal, which is proportional to the product of the wavelength λ and the frequency f, is as follows.

V to λ * f

The wavelength λ of the signal transmitted over the telephone line becomes smaller as the frequency f increases. If the signal is transmitted in the VHF band as in the case of the xDSL modem, the wavelength λ will have a few meters, i.e. the size of the wall in the building. Accordingly, signal reflection will occur in an additional socket, such as socket B of FIG. 1, which is not connected to any device but is electrically connected to the telephone line T via a communication line. In terms of high-speed modems, these additional outlets are considered the stub of a truncated communication line connected to the main transmission telephone line (T). These chips reflect the signal in a way that causes disturbing “notches” in the signal frequency spectrum.

Figure 2 shows a "notch" caused by a socket reflecting a signal with no device connected. The frequency f _notch of the notches induced and the severity of the notches depend on the length L of the extension line shown in FIG. 1.

In addition to signal reflection at socket B, another set of telephones connected to other outlets C and D, in operation, generate additional interference signals to the xDSL transmission in the xDSL data transmission frequency range. For example, signals such as time signals from a radiotelephone base station connected to the socket D may interfere with xDSL data transmission.

Accordingly, an object of the present invention is to provide a terminal for preventing signal disturbance during data transmission of a high speed modem.

This object is achieved by a terminal having the features of claim 1.

The terminal according to the present invention,

A high pass filter separating the signal in the frequency band used by the high speed modem, and

An impedance means connected to said high pass filter,

The impedance means has an impedance matching the impedance of the telephone line in the frequency band used by the high speed modem.

In a preferred embodiment of the present invention, the terminal includes a low pass filter for separating telephone voice signals transmitted in a low frequency band.

This provides the advantage that signal disturbances caused by base stations connected to telephone sets or terminals are suppressed.

In a preferred embodiment of the invention the impedance of the impedance means is asymptotically resistive in the frequency domain.

In a preferred embodiment the impedance is a resistance.

Preferably, the impedance is a resistor with 130 kHz.

In a preferred embodiment of the present invention, the low pass filter and the high pass filter are passive filters.

In a preferred embodiment the cutoff frequency of the low pass filter is approximately 700 Hz.

In a preferred embodiment of the present invention, the cutoff frequency of the high pass filter is approximately 1 MHz.

In an alternative embodiment the low pass and high pass filters of the terminal according to the invention are active filters.

In another embodiment of the present invention, the low frequency band is a POTS frequency band ranging from 0 Hz to approximately 4 Hz.

In an alternative embodiment of the terminal according to the invention the low frequency band is an ISDN frequency band ranging from 0 kHz to approximately 130 kHz.

In a preferred embodiment of the terminal according to the invention the high speed modem is an xDSL modem.

The xDSL modem is preferably a VDSL modem.

In a preferred embodiment of the present invention, the frequency band used by the high speed modem includes a data downstream frequency band and a data upstream frequency band.

The data downstream frequency band ranges from about 0.9 MHz to about 3.5 MHz and the data upstream frequency band ranges from about 4 MHz to about 7.9 MHz.

The low pass filter according to the preferred embodiment has an output terminal connecting the telephone set to the terminal.

In a preferred embodiment of the terminal according to the invention the low pass filter and the high pass filter are connected in parallel with each other.

In a preferred embodiment the telephone line is an unshielded twisted pair (UTP) cable made of copper.

In a preferred embodiment of the terminal according to the invention the terminal is automatically switched to an input terminal connected to the telephone line when the telephone set is not connected to the terminal.

In a preferred embodiment the terminal has detection means for detecting whether the telephone set is connected to the terminal and for controlling the switching unit to connect the high pass filter with the telephone line if no telephone set is connected.

In a preferred embodiment of the terminal according to the invention the impedance of the impedance means is variable.

In another embodiment of the terminal according to the invention the terminal is embedded in a telephone socket.

In an alternative embodiment the terminal is embedded in a telephone set.

In another alternative embodiment the terminal is embedded in a telephone jack.

In another alternative embodiment the terminal is embedded in a telephone extension.

Hereinafter, another exemplary embodiment of a terminal of the present invention will be described in detail with reference to the accompanying drawings.

1 is a telephone wiring structure diagram for explaining the problem to be solved by the present invention,

2 is a view showing a frequency spectrum for voice and data transmission for explaining the problem to be solved by the present invention,

3 is a schematic diagram of a telephone wiring structure having several terminals according to the present invention;

4 is a block diagram of a preferred embodiment of a terminal according to the present invention;

5 is a view showing a preferred embodiment of a terminal including a passive filter according to the present invention.

As shown in Fig. 3 showing the telephone wiring structure, the indoor wall 1 has several telephone sockets, i.e., telephone outlets 2, 3, 4 and 5.

The telephone socket 2 is connected via a line 6 to a service splitter 7 which separates the telephone voice signal from the data signal. The separated telephone voice signal is transmitted in both directions via the signal line 8 to the telephone terminal 9 to which the telephone set 10 is connected via the signal line 11.

The data signal separated by the splitter 7 is transmitted via a data signal line 12 to a high speed modem 13 such as an xDSL modem. The xDSL modem has a remote transmission unit 14 connected to the terminal unit 16 via a line 15. A broadband communication device such as a laptop or personal computer 17 is connected to the terminal unit 16 of the high speed modem 13 via line 18.

The socket 2 is connected to the underground transmission unit 20 of the telephone network 21 via the telephone line 19. The telephone line 19 is usually a UTP cable made of copper.

The interior wall 1 is provided with another socket 3, 4, 5 which is connected to the telephone line 19 via connecting wires 22, 23, 25, 25.

FIG. 3 only shows examples of possible wiring structures in the interior wall 1, the number of sockets and the exact wirings being different and unknown. The terminal 30 according to the invention, which is connected to each additional socket 3, 4, 5, is connected via a connection line 26, 27, 28. A conventional telephone set 29 is connected to a terminal 30b according to the present invention via a line 31. In addition, the radio telephone base station 32 is connected to the terminal 30c according to the present invention via a line 33. The wiring structure may have any form such as a tree structure.

As can be seen from Figure 3, the terminal 30 according to the present invention is connected to all the telephone sockets (3, 4, 5, 6) except for the telephone socket (2) connected to the high-speed modem 13 through the service splitter (7) Is provided.

The terminal 30 according to the present invention may be built in the telephone sockets 3, 4, 5. In an alternative embodiment the terminal 30 according to the invention is embedded in either a telephone set, a telephone jack or a telephone extension.

The terminal 30a shown in FIG. 3 prevents disturbing reflections from the sockets 3 through the lines 22 and 25 to the telephone lines 19, which are transmitted to the high speed modem 13 in the high frequency band. Can interfere with downstream data.

As shown in Fig. 3, the terminal 30b prevents a signal generated when the telephone set 29 is operating while causing interference with xDSL high frequency range xDSL data transmission used by the high speed modem 13.

The terminal 30c prevents, for example, the time signal generated by the radiotelephone base station 32 from interfering with the xDSL data transmission signal within the xDSL high frequency data transmission range.

The small terminal 30 connected to the sockets 3 to 5 suppresses the high frequency wavelength type effect such as signal reflection and the antenna effect which disturbs the factors affecting the signal transmission through the telephone line 19. The disturbance "notch" shown in FIG. 2 is prevented by the small terminal 30 according to the invention, thus reducing the data error that can occur due to this "notch". The terminals 30a to 30c according to the invention shown in FIG. 3 may be adapters which can be plugged into the sockets 3 to 5, or alternatively may be embedded in the sockets 3 to 5. The high speed modem 13 shown in FIG. 3 may be any modem using a high frequency band for data transmission on the telephone line 19, that is, any xDSL modem.

4 is a block diagram of a preferred embodiment of a terminal 30 according to the present invention. The terminal 30 is connected to the socket 3 shown in FIG. 4, for example. The socket 3 comprises a pair of telephone lines 34 and 35 to which the terminal 30 is connected via lines 36 and 37. Connection lines 36 and 37 link the low pass filter 38 to the telephone socket 3. The high pass filter 39 is connected in parallel to the low pass filter 38 by signal lines 40 and 41. The terminal 30 comprises input terminals 42 and 45 for linking the terminal 30 to the telephone socket 3 via lines 36 and 37. The low pass filter 38 is also connected to the terminals 46, 47 of the terminal 30 via lines 44, 45. The telephone set 48 may be connected to the terminals 46 and 47 of the terminal 30 via lines 49 and 50. Although the telephone set 48 may be plugged into the terminal, the terminal 30 according to the present invention works even when the telephone set 48 is not connected to the low pass filter 38. The high pass filter 39 is connected to the impedance means 53 via lines 51 and 52. The impedance means 53 connected to the high pass filter 39 includes an impedance of the telephone line used by the telephone network system and an impedance matching the frequency band used by the high speed modem 13.

The impedance of the impedance means 53 is real impedance, not complex impedance. The value of the impedance means 53 depends on the impedance of the telephone line of the telephone system used. In Germany, the impedance of the impedance means 53 is 130 kHz.

The low pass filter 38 and the high pass filter 39 may be passive filters or active filters. Passive filters are more desirable because they cost less to produce and do not require a power supply for the filter. The cutoff frequency of the filters is variable in the preferred embodiment. In a preferred embodiment the cutoff frequency of low pass filter 38 is approximately 700 Hz and the cutoff frequency of high pass filter 39 is approximately 1 MHz.

The low pass filter 38 is provided for separating telephone voice signals transmitted in both directions to the telephone set 48 within the low frequency band. The low frequency band may be a POTS frequency band ranging from 0 Hz to approximately 4 Hz, and in alternative embodiments an ISDN frequency band ranging from 0 Hz to 130 Hz.

The high pass filter 39 is provided for separating the signal generated on the line 22 in the frequency band used by the high speed modem 13 for data transmission. The high speed modem 13 may be any xDSL modem, in particular a VDSL modem. The high frequency band used by the high speed modem 13 shown in FIG. 3 includes a data downstream frequency band and a data upstream frequency band as shown in FIG. The data downstream frequency band between frequency f ₁ and frequency f ₂ ranges from approximately 0.9 MHz to approximately 3.5 MHz in a preferred embodiment and the downstream frequency band between frequencies f ₃ and f ₄ ranges from approximately 4 MHz to preferred embodiments. Approximately 7.9 MHz. The cutoff frequencies of the low pass filter 38 and the high pass filter 39 are sized according to the high frequency band range used by the high speed modem 13 for data transmission.

In the preferred embodiment, the high pass filter 39 is automatically switched to the telephone socket 3 by the switching unit when a telephone set such as the telephone set 48 is not connected to the terminal 30. To this end, the terminal 30 is a detection means for detecting whether the telephone set 48 is connected to the terminal 30 in a preferred embodiment, and when no telephone set 48 is connected to the terminal 30. The detecting means includes a detecting means for controlling the switching unit to connect the high pass filter 39 with the telephone socket 3.

In another preferred embodiment the impedance of the impedance means 53 is variable. The cutoff frequency and the impedance of the terminal 30 can be adjusted according to the conditions of domestic telephone networks such as Germany and the United States.

5 shows a preferred embodiment of a terminal 30 with a passive low pass filter 38 and a passive high pass filter 39 according to the present invention. The low pass filter 38 and the high pass filter 39 have only passive elements. Passive devices include capacitors and inductors. Both filters 38 and 39 do not require any power source and can be produced at low cost.

Low pass filter 38 includes inductors 54, 55, 56, 56 connected in series between lines 42 and 46. The low pass filter 38 also includes inductors 58, 59, 60, 61 connected in series between the terminal 43 and the terminal 47. The low pass filter 38 also includes inductors 62, 63, 64 connected in series to the capacitors 65, 66, 67.

The high pass filter 39 includes two capacitors 62 and 63 connected in series between the terminal 42 and the line 51. The high pass filter 39 also includes two capacitors 64, 65 connected in series between the terminal 43 and the line 52. Also, as shown in FIG. 5, the high pass filter 39 has a capacitor 66 connected to the inductor 67. In the preferred embodiment shown in Fig. 5, both filters have an inductor and a filter having a constant value. In alternative embodiments the elements in the filters 38 and 39 are adjustable to change the cutoff frequency of the filter. As can be clearly seen in Fig. 5, the terminal 30 according to the present invention has only passive elements, and thus can be produced in a highly integrated manner, which makes the terminal 30 according to the present invention into a very small sized element. In addition, the production cost of the terminal 30 shown in Figure 5 is also very low.

The terminal 30 according to the present invention is disturbed at a place where a plurality of telephone outlets are connected to the same telephone line 19, in particular, a high speed modem 13 such as a VDSL modem is also connected to the telephone line via the outlet 2. Overcome the impact The terminal 30 maintains its functionality and increases the available quality of the high speed data transmission service and the maximum available transmission distance. Available quality can be increased by lowering the bit error rate due to signal notch in the downstream data transmission frequency band or the upstream data transmission frequency band. In addition, the terminal 30 according to the present invention can be produced at low cost and small size. This offers the further advantage that the terminal 30 according to the invention can be embedded in a telephone jack or in a telephone jack in the telephone set itself.

Claims (26)

In the telephone line terminal 30 of the wiring based on the telephone system, Input terminals 42 and 43 for linking the terminal 30 to the telephone socket 3; A passive high pass filter (39) for separating signals in a frequency band used for data transmission by a high speed modem (13) connected to a telephone socket (2) via a service splitter (7), wherein the telephone socket (2, 3) the passive high pass filter 39, which is connected to the underground transmission unit 20 of the telephone network 21, An impedance means 53 connected to the passive high pass filter 39 having a variable impedance matching the impedance of the telephone line in the frequency band used by the high speed modem 13, A passive low pass filter 38 which is connected to the input terminals 42 and 43 of the terminal 30 and separates a telephone voice signal transmitted in a low frequency band; Output terminals 46 and 47 connecting the telephone set 48 to the passive low pass filter 38 of the terminal 30, and It detects whether the telephone set 48 is connected to the output terminals 46 and 47 of the terminal 30, and no telephone set 48 is connected to the terminal 30 to signal at the telephone socket 3; And a detecting means for controlling the switching unit to automatically switch the passive high pass filter (39) to the input terminals (42, 43) when the reflection is not suppressed. delete The method of claim 1, The impedance of the impedance means (53) is a telephone line terminal, characterized in that asymptotically resistive (asymptotically resistive). The method of claim 3, The impedance means (53) is a telephone line terminal, characterized in that the resistance. The method of claim 4, wherein The impedance of the resistor (53) is a telephone line terminal, characterized in that 130 ohms. delete The method of claim 1, The cut-off frequency of the passive low pass filter (38) is approximately 700 kHz. The method of claim 1, A cut-off frequency of the passive high pass filter (39) is approximately 1 MHz. delete The method of claim 1, And said low frequency band is a POTS frequency band ranging from 0 kHz to approximately 4 kHz. The method of claim 1, The low frequency band is a telephone line terminal, characterized in that the ISDN frequency band ranging from 0kHz to 130kHz. The method of claim 1, The high speed modem (13) is a phone line terminal, characterized in that xDSL modem. The method of claim 12, The xDSL modem is a telephone line terminal, characterized in that the VDSL modem. The method of claim 1, The frequency band used by the high speed modem (13) includes a data downstream frequency band and a data upstream frequency band. The method of claim 14, Wherein said data downstream frequency band ranges from approximately 0.9 MHz to approximately 3.5 MHz and said data upstream frequency band ranges from approximately 4 MHz to approximately 7.9 MHz. delete delete The method of claim 1, The telephone line is a telephone line terminal, characterized in that the UTP (unshielded twisted pair) cable made of copper. delete delete delete The method of claim 1, Telephone terminal, characterized in that the terminal 30 is embedded in the telephone socket (3). delete The method of claim 1, Telephone terminal, characterized in that the terminal 30 is built in the telephone jack. The method of claim 1, Telephone terminal, characterized in that the terminal 30 is built in the extension line. The method of claim 1, And a cutoff frequency of the passive low pass filter (38) and the passive high pass filter (39) is variable.

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