KR20000045164A - Internet phone system using cable modem - Google Patents

Abstract

PURPOSE: An internet phone system is provided to be easy to realize an internet phone by connecting a telephone to an internet through a cable modem located at a home or an office instead of connecting the telephone to the internet through an internet phone gate way. CONSTITUTION: An internet phone system comprises a subscriber line interface circuit(21) which functions as an interface with a general telephone(12). A speech CODEC(22) converts an analog speech signal inputted through the subscriber line interface circuit(21) into a digital speech signal, and converts a digital speech signal inputted from an echo suppressing section(23) into an analog speech signal. The echo suppressing section(23) removes an echo speech from the digital speech signal outputted from the speech CODEC(22), and removes an echo speech from a digital speech signal inputted from a cable modem(25) to output the echo-free digital speech signal to the speech CODEC(22). A dual tone multi frequency(DTMF) sensing section(24) senses frequencies of keys in the telephone(10) which are mixed with a digital speech signal from the echo suppressing section(23), and codes the sensed key value. The cable modem(25) packets a select key code from the DTMF sensing section(24) and he digital speech signal from the echo suppressing section(23) to output the packeted signal to a cable network. The cable modem(25) filters a packet inputted through the cable network to output a digital speech signal to the echo suppressing section(23).

Description

An internet phone system using a cable modem

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phone-to-phone type internet phone system, and more particularly, to an internet phone system using a cable modem that allows a general telephone to be directly connected to the Internet through a cable modem. It is about.

In the case of a conventional phone-to-phone Internet phone implementation network, as shown in FIG. 1, the general telephone is connected to the Internet only through an Internet phone gateway that manages the interface between the Internet and a public switched telephone network (PSTN). Internet connection was available. In this case, the general telephone user first dials to the place where the Internet phone gateway is located and reenters the phone number of the other party.

As described above, the conventional telephone user has a problem of causing inconvenience to the user because the user has to go through two numbering processes in order to make an internet call.

In addition, in the related art, a user has to make a phone call to an Internet phone gateway, so there is a problem of separately paying a local call rate (PSTN usage fee).

In addition, in the related art, since the number of ports assigned to the Internet phone gateway is limited, it is impossible to use the Internet phone before the port is assigned, so that when the number of users is congested, it is difficult to allocate the ports, causing inconvenience to the user.

The present invention has been made in order to solve the above problems, instead of connecting a normal telephone to the Internet through a separate Internet phone gateway Internet telephones by connecting directly to the Internet via a cable modem located in each home or office easily The purpose is to provide an internet phone system using a cable modem that can be implemented.

In order to achieve the above object, the Internet phone system using the cable modem according to the present invention comprises: an Internet phone system enabling an internet call through a general telephone, the SLIC in charge of the interface with the telephone; A voice codec for converting and outputting an analog voice signal input through the SLIC into a digital voice signal, and converting the digital voice signal of the other party from which echo sound is removed into an analog voice signal and outputting the analog voice signal to the phone through the SLIC; An echo suppressor for removing echo sound from the digital speech signal output from the speech codec and outputting the echo sound; A DTMF detector for detecting frequencies of the keys provided in the keypad of the telephone mixed with the digital voice signal output from the echo suppressor and then encoding the detected key values and outputting the encoded key values; Cable modem for packetizing the digital voice signal outputted from the echo suppressor and the selection key code outputted from the DTMF sensor and outputting the packet to the echo suppressor by filtering the packet inputted through the cable network. Characterized in that consisting of.

1 is a schematic configuration diagram of a typical Internet phone implementation network;

2 is a schematic diagram of a cable modem network to which the present invention is applied;

3 is a block diagram of an Internet phone system using a cable modem according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: regular telephone 20: Internet phone system

21: SLIC 22: Voice Codec

23: echo suppressor 24: DTMF detector

25: cable modem (CM)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The cable modem network will be briefly described to help understand the present invention.

Cable modem network is a network system that is attracting attention together with ISDN and multi-digital subscriber line (xDSL) in the field of remote access.It is connected to the Internet and intranet to provide subscribers with high speed data transmission speed of Mbps. Provides various services such as video conferencing, web search, etc.

The concept of cable modem networks, which have a wide user base in the United States, is to bring cable TV (CATV) networks into the data communication field. In terms of using coaxial cables, they are similar to each other. A cable modem network connects a coaxial cable to a personal computer (PC) via a cable modem, while connecting the TV to the set-top box after connecting the box. At this time, there may be one PC or multiple PCs connected to the cable modem.

FIG. 2 is a schematic configuration diagram of a cable modem network according to the present invention, in which a plurality of cable modems (CM) are connected to a cable network, and each CM has a customer premises equipment (CPE). A PC or a terminal adapter (TA) and a general telephone are connected, and a cable modem termination system (CMTS) is connected between the cable network and the backbone network.

The CMs appropriately process upstream channel packets input from a PC or a TA and downstream channel packets input from a CMTS in a buffer and a memory so that the subscriber is connected to the CMTS. To be provided with services such as the Internet from the network.

3 is a block diagram of an Internet phone system using a cable modem according to an embodiment of the present invention, wherein the Internet phone system 20 includes a subscriber line interface circuit (SLIC) 21 and a speech codec 22. And an echo suppressor 23, a dual tone multi frequency (DTMF) detector 24, and a CM 25. Here, the SLIC 21, the voice codec 22, the echo suppressor 23, and the DTMF detector 24 correspond to the TA shown in FIG.

The SLIC 21 is responsible for the interface (voltage conversion, ring generation, etc.) with the normal telephone 10.

The voice codec 22 converts an analog voice signal input through the SLIC 21 into a digital voice signal, outputs it to the echo suppressor 23, and removes the echo voice input from the echo suppressor 23. Converts the digital voice signal into an analog voice signal and outputs it to the general telephone 10 through the SLIC (21).

The echo suppressor 23 removes the echo speech from the digital speech signal output from the speech codec 22 and outputs the echo speech to the CM 25, and removes the echo speech from the digital speech signal of the counterpart input from the CM 25. To the audio codec 22.

The DTMF detector 24 senses the frequencies of the keys provided on the keypad of the general telephone 10 mixed with the digital voice signal output from the echo suppressor 23, and then codes the detected key values to encode the CM 25. Will print

More specifically, the tones generated when a key is provided on the keypad of the telephone 10 are 0, 1, 2,... As shown in Table 1 below. , 8, 9, #, * Frequency is determined corresponding to each.

1209 yen 1330 yen 1447 yen 697 Hz One 2 3 770 Hz 4 5 6 852 Hz 7 8 9 941 Hz * 0 #

That is, in the telephone 10, each time the key provided in the keypad is pressed, the high frequency bands (1209 Hz, 1336 Hz, 1477 Hz) and the low frequency bands (697 Hz, 770 Hz, 852 Hz, 941 Hz) as shown in Table 1 are used. A DTMF signal obtained by adding the frequency signals is generated and sent out. For example, when the "5" key is pressed, DTMF signals of 770 Hz and 1336 Hz are transmitted, and when the "0" key is pressed, DTMF signals of 941 Hz and 1336 Hz are transmitted.

The CM 25 packetizes the digital voice signal output from the echo suppressor 23 and the selection key code (e.g., the other party's telephone number code) output from the DTMF detector 24 and outputs the packet to the cable network. The packet input through the filter is filtered to output the digital voice signal of the counterpart to the echo suppressor 23.

Referring to the operation of the Internet phone system according to an embodiment of the present invention configured as described above in detail as follows.

First, in the case of call origination, when the user picks up the handset of the telephone 10 and dials the telephone number of the other party who wants to make an Internet call using the keys provided on the keypad, the telephone 10 signals the frequency corresponding to the telephone number of the other party. (DTMF signal) is generated and output to the CM 25 side through the SLIC 21, the voice codec 22, and the echo suppressor 23, and the DTMF detector 24 is output from the echo suppressor 23. After detecting the signal, the selected telephone number key value is encoded and output to the CM 25.

The CM 25 packetizes the telephone number code received from the DTMF detector 24 and transmits the corresponding data packet to the CMTS through a cable network so that a call with the other party is connected.

When the call with the other party is connected through the above process, the other party's response voice (for example, "hello") is transmitted to the CM 25 through the Internet, the CMTS, and the cable network in the form of a packet. The CM 25 filters the voice packets of the counterpart received through the cable network and outputs them to the echo suppressor 23, and the echo suppressor 23 outputs the digital voice signal from the counterpart received from the CM 25. The echo sound is removed and output to the speech codec 22.

The voice codec 22 converts the digital voice signal of the counterpart received from the echo suppressor 23 into an analog voice signal and outputs the analog voice signal to the telephone 10 through the SLIC 21.

The user starts a conversation with the other party when the other party's voice is heard through the handset of the telephone 10. At this time, the analog voice signal of the user is input from the phone 10 to the voice codec 22 through the SLIC 21, and the voice codec 22 receives the analog voice signal of the caller received through the SLIC 21. The echo suppressor 23 converts the digital speech signal into an echo suppressor 23, and the echo suppressor 23 removes the echo speech from the user's digital speech signal received from the speech codec 22 and outputs the echo speech to the CM 25. .

In the above, the CM 25 packetizes the digital voice signal of the user received from the echo suppressor 23 and transmits the packet to the CMTS through the cable network, and the CMTS transmits the voice packet of the user received from the CM 25 to the Internet. To the other party.

Through the above process, the user can make a call with the other party through the Internet.

In addition, in the case of the incoming call, the voice transmission process between the user and the caller is the same as in the above-described outgoing call, but in the case of the incoming call, the SLIC 21 receives the ring generation signal from the calling party and the ring is received from the phone 10. Generates a voltage to ring and outputs to the telephone 10, and as a result, the telephone 10 rings a ring indicating that there is an incoming call.

On the other hand, if both the calling party and the called party are provided with the Internet phone system 20 shown in FIG. 3, there is no need to use the PSTN during an internet call between the calling party and the called party. Even if the Internet phone system 20 shown in FIG. 8 is provided, the calling party is subject to the billing system of the called party, so that Internet calls can be made at a much lower cost than the conventional Internet phone system.

In addition, the user can attempt to make an Internet call through a one-time numbering process as in a general telephone use method.

As such, the present invention connects a regular telephone directly to the Internet without a separate internet phone gateway, so that a separate PSTN usage fee is not charged, so that an internet call can be made at a much lower cost than a conventional telephone. By allowing the user to connect the phone has an effect that can be convenient for the user.

Claims (1)

In the Internet phone system that enables the Internet call through a regular telephone, A SLIC responsible for interfacing with the telephone; A voice codec for converting and outputting an analog voice signal input through the SLIC into a digital voice signal, and converting the digital voice signal of the other party from which echo sound is removed into an analog voice signal and outputting the analog voice signal to the phone through the SLIC; An echo suppressor for removing echo sound from the digital speech signal output from the speech codec and outputting the echo sound; A DTMF detector for detecting frequencies of the keys provided in the keypad of the telephone mixed with the digital voice signal output from the echo suppressor and then encoding the detected key values and outputting the encoded key values; Cable modem for packetizing the digital voice signal outputted from the echo suppressor and the selection key code outputted from the DTMF sensor and outputting the packet to the echo suppressor by filtering the packet inputted through the cable network. Internet phone system using a cable modem, characterized in that consisting of.