WO2009112919A1

WO2009112919A1 - Connection device for telephone and data communications

Info

Publication number: WO2009112919A1
Application number: PCT/IB2009/000457
Authority: WO
Inventors: Alberto Mariuzzo; Davide Pozza; Francesco Chino; Stefano Bianconi
Original assignee: Telsey S.P.A.
Priority date: 2008-03-10
Filing date: 2009-03-08
Publication date: 2009-09-17
Also published as: ITMI20080390A1

Abstract

The present invention relates to a connection device for telephone and data communications, which comprises a telephone port (P 1) for connecting a telephone cable coming from a telecommunications exchange (TEX, DEX), a data port (P5) for connecting a data cable of a data network, a telephone circuit section (TS) adapted to handle telephone communications, which is electrically connected (ClT) to the telephone port (Pl), a data circuit section (DS) adapted to handle data communications, which is electrically connected (ClD, ClT) to both the telephone port (P l) and the data port (P5); the device further comprises insulating means (P2, P3, P4, P7, IS) adapted to provide galvanic insulation between the circuit sections (TS, DS).

Description

TITLE

CONNECTION DEVICE FOR TELEPHONE AND DATA COMMUNICATIONS

DESCRIPTION

The present invention relates to a connection device for telephone and data communications .

In particular, it relates to a device commonly referred to as "gateway", which is adapted to allow POTS [Plain Old Telephone Service] telephone communications, IP [Internet Protocol] telephone communications, and IP data communications.

Devices of this kind are intended for domestic or small office applications.

As known, high voltages (e.g. caused by lightning) may occasionally be present on the telephone line (generally a telephone twisted pair cable) coming from the telephone exchange; for this reason, traditional wired telephone sets include galvanic insulation means for user protection.

On one side (outwards) these devices are connected to the telephone line, while on the other side (inwards) they are connected to telephone sets by means of a telephone cable and to computers by means of an Ethernet data cable and sometimes also through a switching device, i.e. a so-called "hub" or a so-called "switch".

While telephone sets are equipped with internal galvanic insulation means, computers may however lack adequate internal galvanic insulation means, even though Ethernet interfaces provide galvanic insulation at data transmission level.

The Applicant has realized that the galvanic insulation available in known systems (of this type) may sometimes be neither appropriate nor properly controlled, and relies on the galvanic insulation contained in or provided by other devices. This is the case, for example, when a data connection is created through a USB cable, in that this type of data connection offers no galvanic insulation. The Applicant has also found that the problem of galvanic insulation is even more serious in "data+voice gateways" (typically the data service is based on the ADSL [Asymmetric Digital Subscriber Line] technology and the voice service is based on the VOIP [Voice Over IP] technology, but the data service may also be based on different technologies, such as, for example, VDSL [Very High Speed Digital Subscriber Line]), wherein the telephone circuit section (essentially consisting of the SLIC circuit [Subscriber Line Interface Circuit]) is connected to the external telephone line either directly or by means of other devices, which however do not provide any galvanic insulation or only provide insufficient galvanic insulation.

It is the object of the present invention to overcome the drawbacks of the prior art by providing a connection device for telephone and data communications which can withstand high voltage transients on the telephone cable coming from a telecommunications exchange, thereby protecting the electric and electronic household devices connected thereto, as well as the user thereof.

Said object is achieved through a connection device having the features set out in the appended claims, which are intended as an integral part of the present description.

The present invention is based on the idea of providing the connection device with galvanic insulation means arranged between the telephone circuit section and the data circuit section thereof.

In general, the connection device for telephone and data communications according to the present invention comprises:

- a telephone port for connecting a telephone cable coming from a telecommunications exchange, - a data port for connecting a data cable of a data network,

- a telephone circuit section adapted to handle telephone communications, which is electrically connected to said telephone port,

- a data circuit section adapted to handle data communications, which is electrically connected to both said telephone port and said data port; said device further comprises insulating means adapted to provide galvanic insulation between said circuit sections. The device according to the present invention may also comprise connection means adapted to provide an operational connection between said circuit sections; in such a case, said connection means are distinct from said telephone port, and said insulating means comprise first insulating means associated with said telephone port and second insulating means associated with said connection means.

The device according to the present invention may further comprise power supply means electrically connected to said circuit sections; in such a case, said insulating means are adapted to provide galvanic insulation between the power supply of said telephone circuit section and the power supply of said data circuit section.

The device according to the present invention may further comprise a DECT module electrically connected to said telephone port; in such a case, said insulating means may either be adapted to provide galvanic insulation between said DECT module and said telephone circuit section or be adapted to provide galvanic insulation between said DECT module and said data circuit section; the choice will depend on the arrangement of the DECT module within the device according to the present invention.

Said telephone circuit section may comprise a SLIC circuit.

The device according to the present invention may further comprise switching means electrically connected to said telephone port of the device and to said SLIC circuit.

The device according to the present invention may further comprise an additional telephone port; in such a case, said switching means may be electrically connected to said additional telephone port.

Said switching means may be controlled by said data circuit section, in particular through further connection means; in such a case, said insulating means are adapted to provide galvanic insulation between said switching means and said data circuit section. Said data circuit section may be connected to at least one Ethernet port and/or at least one USB port.

Said data circuit section may comprise a network processor.

Said SLIC circuit may be operationally connected to said network processor; in such a case, said insulating means are adapted to provide galvanic insulation between said SLIC circuit and said network processor.

Said telephone circuit section may comprise a bidirectional low-pass filter electrically connected to said telephone port.

Said insulating means may be adapted to provide galvanic insulation through a magnetic and/or optical and/or capacitive effect, and generally have a broad passband.

The device according to the present invention is typically adapted to allow POTS [Plain Old Telephone Service] telephone communications, IP (i.e. VOIP) telephone communications, and IP data communications; moreover, it is preferably of the type featuring automatic installation, i.e. it can switch itself automatically from POTS telephone communications to IP telephone communications when it detects the presence of the VOIP service in the signal . coming from the external line.

The present invention, and in particular the technical features and advantages thereof, will become more apparent from the following description referring to the annexed drawings, wherein:

Fig.l shows a first embodiment of the present invention,

Fig.2 shows a second embodiment of the present invention,

Fig.3 shows a first alternative solution for the switching means used in the example of Fig.2,

Fig.4 shows a second alternative solution for the switching means used in the example of Fig.2,

Fig.5 shows a third alternative solution for the switching means used in the example of Fig.2, Fig.6 shows a third example of the present invention, and Fig.7 shows a fourth example of the present invention.

Said description and said drawings are to be considered as referring to non- limiting examples; additionally, said drawings are simplified block diagrams.

Fig.l is a simplified block diagram of a connection device GWl for telephone and data communications according to the present invention, also referred to as "gateway".

The device GWl comprises a port P l for connecting a telephone cable, typically a telephone twisted pair cable, coming from a telecommunications exchange; generally, as shown in Fig.l, the external telephone cable arrives at a port PO installed in the user's house, and the port Pl of the device GWl is connected to the port PO through a length of internal telephone cable belonging to the household telephone system; in the example of Fig.l, the household telephone system comprises a number of telephone cables (indicated schematically by a line) to which three traditional-type telephone sets TAl, TA2 and TA3 are connected.

Fig.l shows two exchanges, i.e. a telephone exchange TEX for traditional-type telephone communications and a data exchange DEX for data communications, and a connection element CON.

According to the case, thanks to the element CON the household telephone system can be connected:

- to the exchange TEX only;

- to the exchange DEX only;

- to both exchanges TEX and DEX.

The device GWl comprises a port P 5 for connecting a data cable of a household data network; in the simplest of cases, the household data network consists of one data cable for connecting only one computer; more generally, the household data network comprises a plurality of data cables connected to one another and to the device GWl through a switching device, i.e. a so-called "hub" or a so-called "switch". In the example of Fig. l, the port P5 is of the USB type; however, the device GWl may also have multiple data ports, in particular one USB port and one or more data ports of a different type (e.g. Ethernet), or multiple USB ports, or multiple USB ports and one or more data ports of a different type (e.g. Ethernet).

The device GWl comprises a telephone circuit section TS adapted to handle telephone communications and a data circuit section DS adapted to handle data communications; the two sections TS and DS are operationally connected to each other for several reasons, as will become apparent hereafter.

In the example of Fig.1 , the data section DS essentially comprises an ADSL analog interface, referred to as AFE [Analog Front End], and a network processor NP, while the telephone section TS comprises a bidirectional low-pass filter LPF, switching means SWA, and a SLIC circuit.

As a reminder, a SLIC [Subscriber Line Interface Circuit] is a circuit that can execute all (or almost all) of those functions which are generally referred to as a whole as "BORSCHT" (B="battery feed", O="over-voltage protection", R="ringing", S="supervision", C="codec", H="hybrid", T="testing").

The port Pl is electrically connected directly to the filter LPF, which is electrically connected directly to the switching means SWA, which in turn is connected directly to the SLIC circuit, in particular to the FXS [Foreign eXchange Station] interface thereof; the bidirectional filter LPF allows, among other things, to block the high-frequency noise associated with data signals (e.g. ADSL type) which would otherwise propagate from the ports Pl and P2 to the switching means SWA, as well as to block the high-frequency noise associated with telephone signals (e.g. generated by the SLIC circuit) which would otherwise propagate from the switching means SWA to the ports Pl and P2; the switching means SWA are used for connecting/disconnecting the SLIC circuit to/from the port Pl in accordance with the functional requirements of the device GWl.

The port P 1 is electrically connected indirectly to the interface AFE through galvanic insulation means P2 and electric conductors ClT (telephone section side) and ClD (data section side); this connection is used for transferring the data signals between the port Pl and the data section DS of the device GWl. The interface AFE is electrically connected directly to the processor NP, which is electrically connected directly to the port P5; these connections are used for transferring the data signals, suitably transformed and processed by the processor NP, between the port Pl (which is connected to the external telephone cable) and the port P5 (which is connected to the household data network).

The processor NP is electrically connected indirectly to the switching means SWA through galvanic insulation means P3 and electric conductors C2T (telephone section side) and C2D (data section side); this connection allows the switching means SWA to be controlled by the processor NP; should the switching means be provided through a relay, for example, the galvanic insulation means P3 would not be required, since galvanic insulation would be ensured by the relay itself.

The processor NP is electrically connected indirectly to the SLIC circuit through galvanic insulation means P4 and electric conductors C3T (telephone section side) and C3D (data section side); the purpose of this connection is to allow the SLIC circuit to be controlled by the processor NP and to transfer voice information between the SLIC circuit and the processor NP.

Of course, both the telephone section TS and the data section DS of the device GWl need electric power; Fig.l shows an electric power supply PS of the device GWl subdivided into two parts TPS and DPS galvanically insulated from each other by insulating means IS; the part TPS supplies power to the telephone section TS, while the part DPS supplies power to the data section DS; the galvanic insulation may be obtained, for example, by connecting both parts TPS and DPS to two distinct and separate secondary windings of a transformer.

It can therefore be understood that the telephone section TS and the data section DS are galvanically insulated from each other while still being operationally connected to each other.

The galvanic insulation means may be provided in many different ways, in particular through magnetic, optical or capacitive insulation devices; the means P2 may, for example, consist of a transformer, while the means P4 may consist of an integrated-circuit optical insulator (which is a per se known device). In order to decide how the insulating means should be provided in the various points of the device GWl, it is necessary to take into account, among other things, the bandwidth of the signals to be transferred through the insulating means, whether baseband signals are to be transferred or not (e.g. voltage levels), and whether it is a mono-directional or bi-directional transfer; the means P3 and P4 require level transfers, whereas the means P2 require no level transfers; the means Pl must transfer broadband analog signals (typically ranging from a few hundreds of KHz up to a few MHz in the case of ADSL data signals, or a few tens of MHz in the case of VDSL signals); the means P4 must transfer broadband digital signals (typically ranging from a few KHz up to a few MHz); the means P 3 must transfer very-low-band signals (typically fractions of Hz).

The operation of the device GWl of Fig.1 will now be described in general terms by assuming that the exchange TEX is a telephone exchange adapted to handle traditional telephone signals only and that the exchange DEX is a data exchange adapted to handle data signals according to the ADSL technology and telephone signals according to the VOIP technology.

Initially the element CON connects the household system to the exchange TEX only; the data section DS of the device GWl receives no data signals, and therefore it controls the switching means SWA so as to not connect the SLIC circuit to the port Pl; the telephone sets TAl, TA2 and TA3 of the household telephone system receive and transmit telephone signals from/to the exchange TEX as if the device GWl were not present; the galvanic insulation between the telephone section TS and the data section DS is provided by the means P2, P3 and IS, as well as by the switching means SWA, which are open.

The element CON then connects the household system to both the exchange TEX and the exchange DEX; at this stage, the exchange DEX handles no telephone signals; the data section DS of the device GWl receives data signals through the port Pl and the means P2, but it does not detect the presence of VOIP telephone signals in the received signals, and therefore it controls the switching means SWA so as to not connect the SLIC circuit to the port Pl; the telephone sets TAl, TA2 and TA3 of the household telephone system receive and transmit telephone signals from/to the exchange TEX as if the device GWl were not present; the data network connected to the port P5 receives and transmits data signals from/to the exchange DEX through the interface AFE and the processor NP; the galvanic insulation between the telephone section TS and the data section DS is provided by the means P2, P3 and IS, as well as by the switching means SWA, which are open.

Finally, the element CON connects the household system to the exchange DEX only; at this stage, the exchange DEX handles both data signals and telephone signals; the data section DS of the device GWl receives data signals through the port Pl and the means P2, and detects the presence of VOIP telephone signals in the received data signals, and therefore it controls the switching means SWA so as to connect the SLIC circuit, in particular the FXS interface thereof, to the port Pl; the telephone sets TAl, TA2 and TA3 of the household telephone system receive and transmit traditional telephone signals from/to the SLIC circuit; the VOIP telephone signal is handled by the processor NP, which communicates with the SLIC circuit; the data network connected to the port P5 receives and transmits data signals from/to the exchange DEX through the interface AFE and the processor NP; the galvanic insulation between the telephone section TS and the data section DS is provided by the means P2, P3, P4 and IS.

In all of the three conditions described above, the data section DS is galvanically insulated from the telephone section TS and hence from the external telephone cable, so that it is not affected by any high voltages possibly existing on this cable; it follows that any equipment electrically connected directly or indirectly to the data section DS, in particular through the port P5, as well as the user thereof, will thus be protected.

The device GWl of Fig.1 is an "automatic installation" device; in fact, the switching means SWA are controlled by the data section DS of the device, in particular by the processor NP, and automatically provide a connection between the SLIC circuit and the port Pl when they detect VOIP telephone signals in the data signal received from the exchange DEX; this functionality is highly advantageous. Alternatively, the present invention may provide for "manual installation"; in such a case, for example, the switching of the means SWA will be carried out by a user or an operator; in the simplest of cases, it is conceivable that the connection device for telephone and data communications is only connected to the household telephone network when the household network has already been connected to the data exchange DEX and is no longer connected to the telephone exchange TEX.

It is apparent from the above description that the connection of the device GWl to the household telephone system requires no changes to the system itself; this applies both before and after the activation of the VOIP telephone service.

The device GW2 of Fig.2 differs from the device GWl of Fig.l for the presence of a second telephone port P6 and a different embodiment of the switching means, which are therefore referred to as SWB instead of SWA; there is no difference as far as galvanic insulation is concerned.

In the example of Fig.2, the user's household telephone system is divided into two parts: a pre-existent part connected to the port Pl of the device GW2 and comprising a number of telephone sets TAl , ... , and an additional part connected to the port P6 of the device GW2 and comprising a number of telephone sets TBl, TB2, ... ; the telephone sets TA and TB are all of the traditional type. In the simplest of cases, there is only one telephone set (TBl) connected to the port P6 and no telephone sets are connected to the port Pl ; in a slightly more complex case, only one telephone set (TAl) is connected to the port Pl and only one telephone set (TBl) is connected to the port P6.

In the example of Fig.2, the low-pass filter LPF is bidirectional in order to provide galvanic continuity with low impedance in DC and to only let through low- frequency signals in the telephone band (e.g. having a frequency lower than

4KHz) from the port Pl and from the switching means SWB, so as to block high- frequency signals, in particular coming from the port Pl or the port P2; furthermore, the bidirectional filter LPF allows to block the high-frequency noise associated with data signals (e.g. ADSL type) which would otherwise propagate from the ports Pl and P2 to the switching means SWA, as well as to block the high-frequency noise associated with telephone signals (e.g. generated by the SLIC circuit) which would otherwise propagate from the switching means SWA to the ports Pl and P2.

The switching means SWB may be provided in different manners; Figs. 3 to 5 show three alternatives designated SWBA, SWBB, SWBC.

The alternative SWBA comprises a switch CSWl adapted to be controlled by the processor NP; the switch CSWl can be in two operating conditions; in the first operating condition (shown in Fig.3), the filter LPF and the port P6 are electrically connected to each other, but they are not connected to the SLIC circuit; in the second operating condition, the filter LPF, the port P6 and the SLIC circuit are all electrically connected to one another.

The alternative SWBB comprises a switch CSW2 adapted to be controlled by the processor NP; the switch CSW2 can be in two operating conditions; in the first operating condition (shown in Fig.4), the port P6 is connected to the SLIC circuit, but not to the filter LPF; in the second operating condition, the port P6 is connected to the filter LPF, but not to the SLIC circuit.

The alternative SWBC comprises two switches CSW3 and CSW4 adapted to be controlled by the processor NP; each of these two switches can be in two operating conditions, and therefore the switching means of Fig.5 can be put in four operating conditions; in the first operating condition (CSW3 open and CSW4 open) shown in Fig.5, the port P6 is not connected to anything; in the second operating condition (CSW3 closed and CSW4 open), the port P6 is connected to the filter LPF only; in the third operating condition (CSW3 open and CSW4 closed), the port P6 is connected to the SLIC circuit only; in the fourth operating condition (CSW3 closed and CSW4 closed), the port P6 is connected to both the filter LPF and the SLIC circuit; it is therefore apparent that the alternative referred to as SWBC is the one that offers the highest configuration flexibility.

When the port P6 is connected to the filter LPF, all telephone sets TA and TB receive the same telephone signals; the latter may come from the telephone exchange, e.g. the exchange TEX, or from the SLIC circuit. When the port P6 is connected to the FXS interface of the SLIC circuit, the telephone sets TB exchange telephone signals with the SLIC circuit, and therefore the telephone sets TB receive and make telephone calls through the VOIP service.

The device GW3 of Fig.6 differs from the device GW2 of Fig.2 for the presence of a DECT [Digital Enhanced Cordless Telecommunications] module for local wireless telephony connected (indirectly) to the port Pl ; although it is a telephone module, said DECT module has been represented within the data section DS because, in this example, the DECT module is galvanically connected to the same voltage references (e.g. the ground plane) as the data section DS. According to a slightly different variant of the example of Fig.6, the DECT module is connected (indirectly) to the port P6.

The FXO [Foreign eXchange Office] interface of the DECT module is connected between the filter LPF and the switching means SWB through galvanic insulation means P7.

The control block of the DECT module is connected to the processor NP, for example, in order to allow for configuring and/or monitoring and/or collecting alarms pertaining to the DECT module through the processor NP.

The device GW4 of Fig.7 is very similar to the device GW3 of Fig.6. In this case, the DECT module is galvanically connected to the same voltage references (e.g. the ground plane) as the telephone section TS, and therefore it has been represented within the telephone section TS; in this case as well, the control block of the DECT module is connected to the processor NP; the galvanic insulation means are located between the DECT module and the data section DS (P8 in Fig.7), as opposed to between the DECT module and the telephone section TS (P 7 in Fig.6). According to a slightly different variant of the example of Fig.7, the DECT module is connected (indirectly) to the port P6.

It should be noted that simpler alternatives of the examples of Fig.6 and Fig.7 may provide no functional connection between the DECT module and the processor NP.

*******

Claims

1. Connection device for telephone and data communications, comprising:

- a telephone port (Pl) for connecting a telephone cable coming from a telecommunications exchange (TEX, DEX), - a data port (P5) for connecting a data cable of a data network,

- a telephone circuit section (TS) adapted to handle telephone communications, which is electrically connected (ClT) to said telephone port (Pl),

- a data circuit section (DS) adapted to handle data communications, which is electrically connected (ClD, ClT) to both said telephone port (Pl) and said data port (P5); characterized by comprising insulating means (P2, P3, P4, P7, P8, IS) adapted to provide galvanic insulation between said circuit sections (TS, DS).

2. Device according to claim 1, comprising connection means (C2D, C2T; C3D, C3T) adapted to provide operational connection between said circuit sections (TS, DS), said connection means being distinct from said telephone port (Pl), and wherein said insulating means comprise first insulating means (P2) associated with said telephone port (Pl) and second insulating means (P3, P4) associated with said connection means (C2D, C2T; C3D, C3T).

3. Device according to claim 1 or 2, comprising power supply means (PS) electrically connected to said circuit sections (TS, DS), and wherein said insulating means (IS) are adapted to provide galvanic insulation between the power supply (TPS) of said telephone circuit section and the power supply (DPS) of said data circuit section.

4. Device according to claim 1 or 2 or 3, comprising a DECT module (DECT) electrically connected to said telephone port (Pl), and wherein said insulating means (P7) may be adapted to provide galvanic insulation between said DECT module (DECT) and said telephone circuit section (TS).

5. Device according to claim 1 or 2 or 3, comprising a DECT module (DECT) electrically connected to said telephone port (Pl), and wherein said insulating means (P8) may be adapted to provide galvanic insulation between said DECT module (DECT) and said data circuit section (DS).

6. Device according to any of the preceding claims, wherein said telephone circuit section (TS) comprises a SLIC circuit (SLIC).

7. Device according to claim 6, comprising switching means (SWA, SWB) electrically connected to said telephone port (Pl) of the device and to said SLIC circuit (SLIC).

8. Device according to claim 7, comprising an additional telephone port (P6), and wherein said switching means (SWB) are electrically connected to said additional telephone port (P6).

9. Device according to claim 7 or 8, wherein said switching means (SWA, SWB) are controlled by said data circuit section (DS).

10. Device according to claim 9, wherein said switching means (SWA, SWB) are controlled by said data circuit section (DS) through further connection means (C2T, C2D), and wherein said insulating means (P3) are adapted to provide galvanic insulation between said switching means (SWA, SWB) and said data circuit section (DS).

11. Device according to any of the preceding claims, wherein said data circuit section (DS) is connected to at least one USB port (P5).

12. Device according to any of the preceding claims, wherein said data circuit section (DS) comprises a network processor (NP).

13. Device according to any of claims 6 to 10 and according to claim 12, wherein said SLIC circuit (SLIC) is operationally connected (C3D, C3T) to said network processor (NP), and wherein said insulating means (P 4) are adapted to provide galvanic insulation between said SLIC circuit (SLIC) and said network processor (NP).

14. Device according to any of the preceding claims, wherein said telephone circuit section (TS) comprises a bidirectional low-pass filter (LPF) electrically connected to said telephone port (Pl).

15. Device according to any of the preceding claims, wherein said insulating means (P2, P3, P4, P7, P8, IS) are adapted to provide galvanic insulation through magnetic and/or optical and/or capacitive effect and have a broad passband.

16. Device according to any of the preceding claims, characterized by being adapted to allow POTS telephone communications, IP telephone communications, and IP data communications.

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