|Title of Invention||
SYSTEM AND METHOD FOR PROVIDING IP/INTERNET TELEPHONY.
|Abstract||This invention relates to a method for processing a voice call over an internet by an Internet telephone set for used in a home environment, the internet phone sat having an Internet interface device and a wireless device, the method comprising the steps of receiving, by the Internet interlace device, a signal from a cable network, the signal representing Internet protocol data packets of the voice call and being both modulated in a first format and compressed to match a format of the cable network, demodulating, by the Internet interface device, the signal modulated in the first format, decompressing, by the Internet interface device, the demodulated signal, compressing, by the Internet interface device, the decompressed signal into a format into a home environment, modulating by the Internet interface device, the compressed signal into a second format, wireless transmitting, by the Internet interface device, the signal modulated in the second format to the wireless device; and demodulating and decompressing the signal modulated in the second format in the wireless device.|
|Full Text||FIELD OF THE INVENTION
The present invention generally relates to a system and method tor
providing internet telephony. In particular, the present invention relates
to a system and method of providing a wireless internet telephone
system over either a regular dial up telephone or a cable network.
One of the primary reasons for interest in offering Internet Protocol
(IP)/internet telephony services is the pricing structures currently in
place for the data service, and voice service offered by telephone
operators. Long distance voice service can be thought of as "demand data"
service, where the user pays a premium for the instantaneous access to a
64 Kbps channel (voice grade channel in the US). Widely publicized,
promotional type pricing for this service is on the order of $.10 a minute.
By contrast, data service offered by telephone operators, such as that
offered for a T-l connection (24 voice quality data lines, for a 1.544 Mbps
connection) is priced at approximately $1000/month, which works out to
$.001 a minute per voice line. In the very near future, cable operators
will place extreme pressure on even the data service rates for telephone
operators, as cable modem will allow cable operators to offer hundreds of
Kbps effective throughput for approximately $50/month.
The basic idea of IP/internet voice telephony is to digitize your
voice as you talk on the phone and send the digitized data as IP
packets to the Internet. An IP voice device can be embedded within
an Internet connection device such as a modem, a set-top-box, or a
computer. It can be also built as a stand alone product. The stand
alone IP voice device, for example, may provide an Ethernet jack
which can be connected with an Internet connection device and other
LAN devices. The IP voice device may also include interfaces to
connect regular phone handsets. The quality of speech heard through
a normal telephone line requires 64kbits/s bandwidth. However, most
current internet connections have less bandwidth, such as 28.8 Kbps.
or 56 Kbps modem. Furthermore, even if a fast connection device is
used, such as an ISDN, or Cable Modem, the Internet network itself is a
shared medium and has limited bandwidth. Therefore, audio codecs
are usually embedded to compress the voice data.
To guarantee the interoperability between IP voice devices from
different vendors, the International Telecommunications Union (ITU)
developed H.323 as the standard for telephony over IP network.
H.323 defines common procedures for call setup, data compression,
and data transport.
In a general sense, IP telephony can be thought of as providing a
"virtual" point to point connection for voice services over Internet. An
IP voice device is basically a gateway to connect the regular telephone
system to the Internet. The following example demonstrates how a
call would be placed. A user in Indianapolis wants to call a friend in
Paris. He picks up his IP voice device handset (or activates a virtual
handset on a computer screen for a "built-in" version) and hears a
dial-tone like a regular telephone dial-tone. Then, he dials his friend's
Paris phone number. The call travels over the Internet to some
Switching Server provided by the IP telephony service provider. The
Switching Server will connect the call to his friend's IP voice device
and initiates the call. If his friend has only a regular telephone, the
Switching Server will connect the call to a gateway in Paris. The
gateway in Paris then initiates a call over the public switched
telephone network (PSTN) to the local Paris number. The cost to make
phone calls between Indianapolis and Paris using two IP voice devices
is only the Internet access fee. If one party uses a regular telephone,
the extra charge is merely that of a local dial call.
Depending on the Internet connection, there are at least two
methods for making calls using an IP voice device: dial-up connections,
and direct connections. With a dial-up connection, a user first calls an ISP
(Internet service provider) over a regular dial-up line to set up an
Internet connection. Then, he will use the IP voice device handset to dial
the phone number of the person he is calling. The present applicants
recognize one problem with this approach is that the recipient must be
online waiting for the call. So, the sender may have to first call the
recipient using a regular phone to make the appointment. With a direct
connection, a user places a call using the IP voice device just as he does
with the regular telephone. The direct connection indicates a permanent
open channel to the Internet such as ISDN, or a cable access device. For a
a dial-up connection call phone that has been called want ring unless
the Internet connection is already established for this phone. Flora
direct connection call, a phone would ring like a norrmal telephone.
There are many advantages to IP/Internet telephony. One such
advantage is reduced cost as described above. A low bit rate audio oodec
embedded in the IP voice device enables voice calls over a 28.8.kbps
modern. For a small reduction in voice quality, a person's monthly
phone bill will be greatly reduced. If IP voice device used together with a
cable modern, the private service network phis high bandwidth of the
cable modern will provide very good sound quality. Even if the voice
quality provided by a IP/Internet voice device is unsuitable for all phone
communications, a IP/Internet voioe device may be useful as a second-
in residential phone. Also, the H.323 standard supports several well
defined, conference modes and, therefore, IP voice device is able to be
used for multipoint oonference calls. A "wreb" dial-in service is
advantageous for technical or customer support Unas because, for
example, an Internet address of a company's IP voice device can be
embedded in the company's web page and costomers can then call the
company simply by "clicking on" that Internet address. The cost
associated with toll-free (800" number) telephone numbers will be
reduoed as a result.
In addition, MSOs (cable television system operators) have recently
become interested in adding inexpensive telephony services using a
combination of an MBO's private HFC (Hybrid Fiber Coax} network and
the public Internet. Voioe signals are converted to digital values and
transported across the networks using various established and proposed
Internet protocols as IP (Internet protocol packets.
Rafcrenoe D1 (WO 97 29581 A) discloses a transmission system,
which enables users to have a voice conversation via the Internet. D1
utilises the PSTN to connect with an internet service provider. The
system disclosed by D1 includes transmitting a telephone call to the
PSTN and an originating voice engine, which oompresses the signal for
internet to a receiving voice engine. The receiving voice engine
decompresses and demodulates the received signal and provides the
signal to the PSTN (31). The PSTN compresses the signal into a format
for transmission therealong for receipt by a receiving telephone. This
system compresses and decompresses a signal into a format suitable for
transmission by the PSTN. Furthermore, the compression and
decompression of the signal is performed at the PSTN, remotely from the
ends of the established communication channe. Thus, although this
system eliminates most long distance charges associated with a voice
call, there are still local charges associated therewith and possibly long
distance charges on either side of the communication channel associated
with contacting the internet service provider.
Reference D2 WO 98 11703 was published 19 March 1998.
However, there are also problems associated with existing
IP/ Internet telephony systems. For example, the above-described
systems involve some combination of additional or revised POTS (Plain
Old Telephone System) wiring, additional or revised cable network wiring,
or additional network interface boxes. In addition, any connection which
replaces a PSTN (public switched telephone network) service (such as
reuse of the existing POTS wiring within the home to replace PSTN
services with HFC telephony services) may be required to supply so
called life-line" services. Some of these options require professional
installation which may be costly, time consuming, and inconvenient for
SUMMARY OF THE INVENTION
The invention resides, in part, in recognition of the above-described
problems and, in part, in providing a system and method for solving these
problems. In particular, the inventors recognize that the described
problems are solved by providing a voice call over an Internet connection
by receiving a signal from a cable network. The signal represents internet
protocol data packets of the voice call and is both modulated in a first
format and compressed to match a format of the cable network. The
signal is demodulated and decompressed. The signal is next compressed
into a format of a home environment, modulated into a second format and
wirelessly transmitted to a wireless device. The signal is then
demodulated and decompressed in the wireless device. The inventors also
provide a system including the elements necessary to carry out this
An aspect of the present invention involves providing an internet
telephony system using a wireless connection such as via the
unregulated 900 MHz cordless phone spectrum or other spectrum
allocated for wireless communications to provide an RF link between an
IP connection device, a network interface box or set-top box; and one or
more wireless handsets. A processing/ control element in the network
interface box would run the required IP protocols to establish and
manage call set-up and teardown (currently defined within ITU-T H.323),
translate the digital voice signal between IP and the local RF link
protocol, and provide the RF base station function for the handsets).
Each handset would incorporate the other end of the RF link, and A/ D
and D/A functions to convert the voice signal to and from digital packets,
and potentially apply some compression algorithm to improve bandwidth
utilization. In a handset design which does not incorporate enough
processing power to perform the compression function, this function
could potentially reside in the network interface box.
Another aspect of the present invention involves a machanism to
establish a wireless interface to a telephone handset through a settop
box that is tied into a cable network such as a hybrid coaxial cable
Another aspect of the present invention involves using a standard
protocol such as the Internet Protocol to maintain a digital connection
into a cable network while using an RF link to transmit compressed
voice/data information between a telephone device such as a telephone
handset and an interface unit such as a settop box.
Aspects of the present invention also involve providing for
eliminating the need to add wiring, such as POTS wiring, to accommodate
one or more handsets, or alternatively eliminating the need to add
multiple cable drops and adapters such as POTS/HFC adapters. A
wireless feature in accordance with aspects of the invention provides for
coupling a network interface box to an existing cable outlet and for
adding handsets as required without installation of additional outlets. In
addition, aspects of the invention provide for multi-line Internet phone
calls without rewiring. Another aspect of the invention involves adding
an analog trunk interface wherein an IP voice device can be connected to
a PBX device for providing an Internet PBX. For example, a user could
dial a prefix, such as "9" to make a regular outside phone call, or dial a
different prefix, such as "8" to make an Internet phone call.
In accordance with another aspect of the present invention, an IP
voice device or a set top box provides for connecting to external
equipment, such as a PC or Workstation, and utilization of computation
power of external devices for providing additional features such as IP
FAX service or video conferencing.
BRIEF DESCRIPTION OF THE DRAWING
The invention may be better understood by referring to the
accompanying drawing in which:
Figure 1 shows, in block diagram form, an embodiment of a system
incorporating aspects of the invention; and
Figures 2 through 7 show, in block diagram form, embodiments of
portions of the system shown in Figure 1.
Figure 8 is a flow chart illustrating a method of operation according
to the principles of the present invention.
In Figure 1, a system constructed in accordance with aspects of the
invention comprises a PSTN network and a cable network coupled to a
cable modem termination system. The PSTN Network and/or Cable
Network provide alternative paths for coupling the system shown to the
Internet, e.g., to an Internet service provider (ISP). The cable modem
termination system is coupled to a gateway, such as in a home
environment, that comprises a cable modem network interface and first
and second codecs for coupling to a conventional wired telephone via a
subscriber line interface unit and/or to a wireless telephone unit via an
RF modem interface, respectively.
Data transmission between the various units shown in Figure 1
occurs as follows. Data transmission between the PSTN network and the
cable modem termination system shown in Figure 1 (path 1 in Figure 1)
may occur in 64 Kbps/voice line format or in Tl or higher hierarchy.
Data in the cable network (e.g., path 2 between the cable network and the
cable modem termination system in Figure 1, or path 2 between the cable
modem termination system and the cable modem network interface unit
in the gateway in Figure 1) may be carried over TCP/IP compressed at
various rates or uncompressed linear at 64 Kbps/voice line. Data
transmission between the cable modem network interface and the first
codec (path 3 in Figure 1) may occur in linear PCM format at 64
Kbps/voice line. Data transmission between the cable modem network
interface and the second codec (path 4 in Figure 1) may occur in linear
format at 64 Kbps/voice line or compressed at various rates. Data
communication on path 5 in Figure 1 (between the first codec and the
subscriber line interface unit) may be in companded format at 64
Kbps/voice line. Data communication via path 6 in Figure 1 (between the
second codec and the RF modem interface) may be in linear format at 64
Kbps/voice line or in compressed format at various rates. Data
communicated to and from the subscriber line interface unit (path 7 in
Figure 1) may occur in analog format (e.g., for an RJ11 connector) and
data communicated to and from the RF modem interface (path 8 in Figure
1) may occur in RF digital modulation format.
In embodiments shown in Figs. 2 and 3, IP telephony compression
algorithms, call setup, and a cordless telephone adapter are incorporated
into an IP connection device or a client server. An example of an
embodiment of such a device is a device referred to as a Network
Computer (NC) which is a computer similar to a personal computer (PC)
that is intended primarily for providing an interface to the Internet. That
is, a network computer is intended primarily to provide computing power
and features sufficient, for example, to connect to the internet, execute
web browser software and provide email capability. A cordless telephone
adapter in accordance with aspects of the invention would allow the
convenience to call from any room in a house without expensive rewiring.
The phone would ring only when there is an incoming IP phone call, and
would present dial tone, etc. when used to place a call.
Two exemplary embodiments of an IP connection device having
a cordless phone interface are shown in Figures 2 and 3. The system
shown in Figure 2 utilizes an analog cordless telephone interface such
as CT-1 (46/49 MHz). The system shown in Figure 3 uitlizes a digital
900 MHz spread spectrum cordless telephone interface. The analog
cordless IP voice device may provide a lower cost solution. However, a
digital 900 MHz cordless IP voice device may be more advantageous in
terms of voice quality and expandability. For example, a digital
cordless phone typically provides better voice quality due to the noise
cancelling capability of the digital system and a digital cordless IP
voice device may have more than one handset. Also, a cordless IP
voice device such as that shown in Figure 2 and/or 3 may be used for
data service when used together with wireless modem.
The systems shown in Figures 2 and 3 may include a voice codec
for compressing and decompressing the voice data if the modem of the
IP connection device is running at low speeds. Table 1 lists some
popular standard voice codec algorithms and their associated data
Table 1 Voice compression standards
Figure 2 shows a client server device including IP voice features
which, for example, may be included on an IP voice adapter card
included in the client server device. The IP voice feature includes a
CT-1 subsystem comprising RF transmitter circuitry Tx and receiver
circuitry Rx, a programmable PLL synthesizer, a baseband (audio)
processor, and a microprocessor interface. The components Tx and Rx
and the PPL synthesizer are used to modulate and demodulate RF
signals for transmission and reception of the wireless telephone
signals. A duplexer is used to separate the transmit and receive paths
of the RF communications. As discussed before, a PCM codec
integrated with filters may be needed to provide A/D and D/A
conversions and compression, as well as the transmit and receive
filtering of the signals. The digital signal processing (DSP) unit may be,
for example, an integrated circuit (IC) that implements the voice codec
under the control of the CPU (central processing unit) which may be a
microprocessor. The CPU provides the central control of the wireless
IP interface device shown in Fig. 2. The CPU is connected to the
various components of the device via a data control bus. The CPU has
a built in memory for storing the required control codes, including
implementation of the H.323 standards and the TCP/UDP/IP protocols.
Figure 3 shows another exemplary IP connection device having a
digital cordless phone interface such as a 900 Mhz interface. A
baseband device usually includes a spread-spectrum modem, an audio
engine (PCM, DTMF, etc.), a voice codec, and a microcontroller. The
components Tx and Rx and the PLL synthesizer are used to modulate
and demodulate RF signals for transmission and reception of the
wireless telephone signals, to and from the wireless handset. A
duplexer is used to separate the transmit and receive paths of the RF
communications. A DSP unit is used to implement the voice codec
under the control of the CPU. The CPU, or central processor, provides
the central control of the wireless IP interface device as shown in Fig.
3. The CPU is connected to the various components of the device via a
data control bus. The CPU has a built in memory for storing the
required control codes, including impelmentation of the H.323
standards and the TCP/UDP/IP protocols.
Another aspect of the present invention is a wireless internet
telephony system to be connected to a cable network. A network
architecture in accordance with the principles of the present invention is
shown in Figure 4.
In Figure 4, an interface to cable network(100) comprises a cable
modem termination in the physical layer that has a bi-directional channel
connected to the hybrid fiber coax network (105). The physical layer
modulation scheme may comprise, for example, Quadrature Amplitude
Modulation (QAM). The transport mechanism may comprise TCP/IP. In
order to enable the voice application over the cable modem, the network
interface unit may employ a protocol such as H.323 over TCP/IP. This
enables signaling, call set up and other functions. The voice (fax and
analog modem is included in this paradigm) data itself may be carried in
a compressed or uncompressed format. For example, companded voice
data at 64 Kbps can be carried over the cable network embedded in
TCP/IP packets. Alternatively, it may be compressed using one of many
voice compression methods and carried over the cable network
embedded in TCP/IP packets. Certain types of data cannot be compressed
(example fax or analog modem) and need to be carried in a linear format.
Figure 4 also depicts a wireless interface (104) to a plurality of
handsets or receiver devices (101, 102, 103...). The protocol between the
base device (100) and the handsets may be entirely proprietary or some
standard interface. Additionally, the data format or voice (compressed in
one of many possible algorithms or uncompressed) may be different in
the RF network as compared to the format in which the voice was carried
over the HFC network.
Advantages associated with maintaining the same data format (e.g.,
compression scheme) in the wired (cable) and wireless network are:
1. only a single encoding/decoding process is necessary which, in a home
environment, can take place at the wireless handset or mobile terminal
(multiple transcoding processes normally result in degradation of the
original source material); and
2. the base station (e.g., in the home) is transparent to the data from the
handset or mobile terminal.
An advantage associated with maintaining different data formats
(e.g., compression scheme) in the wired (cable) and wireless network is
that certain compressed formats are specifically suited to be carried over
certain transmission channels. Channel errors, depending on how they
occur, can cause different degradation to the source material depending
on the compression scheme that is employed. The wired and wireless
environments are very different in terms of channel characteristics.
Therefore, tailoring the coding scheme to match the characteristics of the
channels may have some benefits in the overall system design.
Figure 5 shows further details of an exemplary embodiment of
cable set-top box (100) in Figure 4. The cable channel (91) that carries
both downstream and upstream data is usually frequency division
multiplexed to enable simultaneous channels of operation. Further,
within a specific channel, due to the nature of the shared cable medium.
multiple users may signal using a time division multiplexed access
mechanism. This task is coordinated by the head end.
The cable interface (40) is a network interface unit (NIU)
comprising of a modulator/demodulator pair and a processing unit for
interpreting the incoming data stream and messages. One of the
transport mechanisms employed is TCP/IP. The NIU receives data,
demodulates decodes and extracts the information pertaining to specific
voice channels in this application. It is also responsible for maintaining
signaling information with the external network (for example using the
H.323 protocol stack or any other commonly used signaling stack used in
telephony). Additional features such as caller ID, messaging, voice mail
etc. are features that are supported by the NIU. This is enabled by its
interface with the Caller ID block (50), the external digital signal
processor (10) with an embedded microprocessor (5) that coordinates the
task of messaging, and voice compression/decompression as necessary.
The incoming messages are stored in compressed or uncompressed,
format in the message memory(60). Other system architectures may be
used wherein the messages are stored in message memory in yet another
compressed format to increase the time over which messages can be
, stored in a given amount of available memory. This task of additional
compression/decompression may take place in DSP unit 10. The code
memory (70) contains the code for the DSP engine. The RF cordless
circuitry (20) is responsible for communicating with the handsets or
mobile terminals and exchange specific information intended for each
device. In addition to the exchange of data, 20 is also responsible for
exchanging signaling and status information. The system shown in Figure
5 includes a common bus (80) between the functional components for
data exchange, but a generalized architecture need not be limited to the
bus structure shown in Figure 5. Additionally, messaging information
and caller ID information are exchanged between 100 and the handsets or
mobile terminals through the RF/cordless circuitry.
Figure 6 shows an exemplary embodiment of the receiver/set-top
box 100 described earlier in regard to Figure 4 and referred to as unit
700 in regard to Figure 6. The transmit and receive signals into the cable
network through the RF connector (796) are kept isolated using a
diplexer (795). The cable tuner (705) and demodulator (710) convert the
digitally modulated signal (for example QAM) into a composite digital bit
stream which is delivered to a Medium Access Control - MAC (720) block
that performs the task of separating information into logical transport
streams. Additionally, unit 720 is responsible for synchronizing with the
cable head end in order to provide the settcp box access control to the
common cable medium for return channel information. The burst
modulator (740) and power amplifier(730) create and send data in the
return channel path back into the cable network.
The RF processing chain for processing the digital information from
the cable network starts with the interface, or input/output (I/O) unit
(760) which may be implemented as an application specific integrated
circuit (ASIC) and which interfaces with a cordless phone processing unit
(750), that also may be part of an ASIC or a separate ASIC, to create
individual links with handsets or mobile receivers. Unit 750 is coupled to
memory units DRAM 765 and ROM 770 for receiving stored processing
instructions and for temporary data storage during processing. The data
intended for each individual handset or mobile receiver may be time
slotted, modulated and sent on the RF link through the RF connector
(797). Additional information streams processed by the MAC processing
block (720) may be directed to an ethernet port (783) through an
ethernet controller (781) or an USB (Universal Serial Bus) port (784)
through an USB controller (785) or an RS232 interface (791) through an
The various functions shown in Figure 6 are connected to bus 721
for communication of data and control information between the functions
and between the functions and CPU 786 which controls the operation of
the functions in device 700. Also coupled to bus 721 are memory units
775 and 780 for storing control programs and data for CPU 786 and other
functions in device 700. Power for unit 700 is provided by power supply
792. Also, while many of the processing blocks shown in Figure 6 may be
optional depending on the specific application or product, the system
shown in Figure 6 illustrates the composite nature of the data coming
over the cable system. The path for the voice channels are of particular
interest in regard to the present invention.
Fig. 7 shows a block diagram of an implementation of a wireless
handset 101. The handset 101 comprises a DSP unit 201 including a
microprocessor 210, a speaker, earpiece, RF circuitry and a keypad.
The microprocessor 210 controls the various components of the wireless
handset 101 via a system bus 202. The RF circuitry is connected to a RF
antenna for transmitting and receiving RF wireless signals. A keypad 204
is used for an user to dial a phone number and for controlling other
functions of the wireless phone. The DSP converts the analog signal into a
digital signal to be transmitted over the RF spectrum if a digital
| transmission system is used. Memory 203 stores the program codes to be
executed by the microprocessor 210.
It is to be understood that the embodiments and variations shown
and described herein are illustrations only and that various modifications
may be implemented by those skilled in the art without departing from
the scope and spirit of the invention.
Figure 8 shows a flow chart illustrating a method of operation
according to the principles of the present invention. At step 802, a signal
is received by, for example, by the cable interface 40 of unit 100. This
signal is demodulated by cable interface 40 into a demodulated signal at
step 803. The unit may decide to further compress or decompress this
demodulated signal under the control of the DSP unit 10 as described
before. The DSP then causes this signal to be further modulated at step
805 by the RF/Cordless circuitry 20. This further modulated signal is
then transmitted wirelessly to a wireless unit, for example, as shown in
Fig. 7. After receiving this further modulated signal at the wireless unit,
the wireless unit then demodulates this signal for completion of the IP
It is to be understood that the embodiments and variations shown
and described herein are illustrations only and that various modifications
may be implemented by those skilled in the art without departing from
the scope and spirit of the invention.
1. A method for processing a voice call over an Internet by an Internet telephone set
for used in a home environment, the Internet phone set having an Internet interface
device and a wireless device, the method comprising the steps of:
receiving, by the Internet interface device, a signal from a cable network, the signal
representing Internet protocol data packets of the voice call and being both modulated
in a first format and compressed to match a format of the cable network;
demodulating, by the Internet interface device, the signal modulated in the first
decompressing, by the Internet interface device, the demodulated signal;
compressing, by the Internet interface device, the decompressed signal into a
format of a home environment;
modulating, by the Internet interface device, the compressed signal into a second
wirelessly transmitting, by the Internet interface device, the signal modulated in the
second format to the wireless device; and
demodulating and decompressing the signal modulated in the second format in the
2. The method of claim 1, wherein the first format is H.323 compliant.
3. The method of claim 1, wherein the first format comprises a same modulation
scheme as the second format.
4. The method of claim 1, wherein the first format comprises a different modulation
scheme as the second format.
5. An Internet telephone set for used in a home environment for processing a voice
call over an Internet, comprising:
means for receiving, demodulating and decompressing a signal representing
Internet protocol data packets of the voice call, the signal being received from a cable
network, modulated in a first format and compressed in a format of the cable network;
means for modulating the signal into a second format and compressing the signal
into a format of a home environment for wireless transmission of the modulated and
compressed signal; and
a wireless device including means for demodulating and decompressing the signal
for completion of the voice call.
6. The Internet phone of claim 5, wherein the first format is H.323 compliant.
7. The Internet phone of claim 5, wherein the first format comprises a same
modulation scheme as the second format.
8. The Internet phone of claim 5, wherein the first format comprises a different
modulation scheme as the second format.
9. The Internet phone of claim 5, wherein an interface between the modulating and
compressing means and the wireless device is a cordless telephone interface.
10. The Internet phone of claim 9, wherein the cordless telephone interface is
11. The Internet phone of claim 10, wherein the analog cordless telephone interface
is CT-1 compliant.
12. The Internet phone of claim 9, wherein the cordless telephone interface is digital.
13. The method of claim 1, wherein an interface between the Internet interface
device and the wireless device is a cordless telephone interface.
14. The method of claim 13, wherein the cordless telephone interface is analog.
15. The method of claim 14, wherein the analog cordless telephone interface is CT-1
16. The method of claim 13, wherein the cordless telephone interface is digital.
This invention relates to a method for processing a voice call over an internet by
an Internet telephone set for used in a home environment, the internet phone
sat having an Internet interface device and a wireless device, the method
comprising the steps of receiving, by the Internet interlace device, a signal from
a cable network, the signal representing Internet protocol data packets of the
voice call and being both modulated in a first format and compressed to match a
format of the cable network, demodulating, by the Internet interface device, the
signal modulated in the first format, decompressing, by the Internet interface
device, the demodulated signal, compressing, by the Internet interface device,
the decompressed signal into a format into a home environment, modulating by
the Internet interface device, the compressed signal into a second format,
wireless transmitting, by the Internet interface device, the signal modulated in
the second format to the wireless device; and demodulating and decompressing
the signal modulated in the second format in the wireless device.
|Indian Patent Application Number||IN/PCT/2000/150/KOL|
|PG Journal Number||46/2008|
|Date of Filing||20-Jul-2000|
|Name of Patentee||THOMAS LICENSING S.A.|
|Applicant Address||46, QUAI A. LE GALLO, 92648 BOULOGNE CEDEX|
|PCT International Classification Number||H04M 7/00|
|PCT International Application Number||PCT/US1999/01631|
|PCT International Filing date||1999-01-27|