JP2000059834A - Digital telephone transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital telephone transmitter that uses a telephone line network consisting of an electric wire cable and an optical fiber cable for high speed digital transmission. SOLUTION: In this digital telephone transmitter where a toll center 1 and a terminator 2 installed in the vicinity of a subscriber side MODEM 31 are interconnected with an optical fiber cable 4 and the terminator 2 and the subscriber MODEM 31 are interconnected with an electric wire cable 5, the toll center 1 is provided with a digital processing section 111 being a component of a station side MODEM 11 and the terminator 2 is provided with an analog front end section 112 consisting of an A/D converter 113 and a D/A converter 114 in components of the station side MODEM 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital telephone transmission apparatus, and more particularly, to a digital telephone transmission apparatus for performing high-speed digital transmission using a telephone line network consisting of electric cables and optical fiber cables.

[0002]

2. Description of the Related Art Several types of digital subscriber line technology have been developed for implementing high-speed digital transmission using electric cable 5. That is, these several types of digital subscriber line technologies include asymmetric digital subscriber line technology (hereinafter, referred to as ADSL), high-speed digital subscriber line technology (hereinafter, referred to as HDSL), and ultra-high-speed digital subscriber line technology. (Hereinafter referred to as VDSL),
Other digital subscriber line technologies have been developed.
These digital subscriber line technologies are collectively called xDSL.
Is expressed as

Here, a conventional example of a digital telephone transmission device employing xDSL will be described with reference to FIG. xDS
The digital telephone transmission apparatus of FIG. 2 which employs the L, the central station 1 has a plurality of station modems 11 compatible with xDSL technology, and the station modem 11 and the subscriber modem 31 compatible with xDSL technology are connected to each other. Are all configured by the conventional electric cable 5 for transmission.

[0004] Recently, the electric cable 5 has been converted to an optical fiber cable to realize high-speed digital transmission. In particular, a fiber-to-the-curve FTTC that extends an optical fiber cable 4 to the vicinity of a subscriber-side modem device and performs transmission using a conventional wire cable 5 only in a short distance section beyond the optical fiber cable 4 is a digital telephone transmission device. It is considered to be the mainstream of digital telephone transmission as being the most ideal in both overall cost and performance. In Japan as well, an optical fiber cable is used as an optical π telephone network or an optical PDS telephone network to connect a cable 5 extending from the central office 1 to a terminating device 2 attached to a member such as a telephone pole near the subscriber-side modem device 31. An optical fiber cable replacement plan has been formulated.

Referring to FIG. 3, a conventional example of a digital telephone transmission apparatus for performing high-speed digital transmission by forming a telephone line network composed of an electric cable 5 and an optical fiber cable 4 will be described. The terminating devices 2 in the vicinity of the modem device 31 are connected via an optical fiber cable 4, and the terminating device 2 and the subscriber modem device 31 are connected via a wire cable 5. In this embodiment, the office-side modem device 11 is arranged on the central office 1 which is the starting end of the optical fiber cable 4.

Another conventional example will be described with reference to FIG. In this embodiment, the central office 1 and the subscriber side modem 3
The end devices 2 near one are connected via an optical fiber cable 4. Terminating device 2 and subscriber-side modem device 31
Are connected via an electric cable 5. And
Focusing on the office-side modem device 11, unlike the conventional example of FIG. 3, this is located on the terminal device 2 side fixed to a telephone pole near the subscriber-side modem device 31 at the end of the optical fiber cable 4. Have been.

[0007]

The advantages and disadvantages caused by whether the office-side modem device 11 is arranged at the central office 1 or the terminating device 2 will be described below. Referring to the conventional example shown in FIG. 3, the arrangement of the office-side modem device 11 is collectively arranged on the central station 1 side as in the conventional example of FIG. However, as compared with the conventional example of FIG. 2, when supplying the xDSL modulated signal to the optical fiber cable 4, optical-electrical converters 13 and 23 for converting light into electricity or converting electricity into light are required, respectively. It is said. By the way, since the optical fiber cable 4 is a transmission path for transmitting digital optical signal information only by turning on and off the light, when a complicated analog signal such as an xDSL modulation signal is to be transmitted, a specially examined circuit element is required. Need to be used and addressed using special circuit technology,
In this respect, there are practical difficulties. And many subscribers 3
In addition, the flexibility of designing a digital telephone transmission apparatus adopting xDSL when multiplexing and transmitting is used is lost.

[0008] Referring to another conventional example shown in FIG.
A direct electric cable 5 is connected between the
FIG. 2 which is currently in practical use in that it is connected via
Is the same as the conventional example. In this case, the conventional example of FIG. 4 can be configured by relocating and using the office-side modem device 11 used in the conventional example of FIG.
It is convenient. However, the terminating device 2 near the subscriber-side modem device 31 generally has a limited space for accommodating communication equipment, and it is difficult to arrange a large number of office-side modem devices 11 in a limited space. Therefore, many subscribers 3
If they request high-speed digital transmission services, they may not be able to respond. Since the terminating devices 2 are distributed and formed at many locations, the maintenance of the office-side modem device 11 distributed at these multiple locations,
When a modem device is replaced due to a change in a standard, a failure, or other reasons, the replacement cannot be performed collectively. This is the biggest problem of the conventional example of FIG.

According to the present invention, the digital processing unit 111 of the configuration of the central-side modem device is arranged in the centralized station 1, and
A digital telephone transmission device that solves the above-described problem by providing an analog front end unit 112 including an A / D converter 113 and a D / A converter 114 in the configuration of the central office modem device in the termination device 2 is provided. Is what you do.

[0010]

Means for Solving the Problems Claim 1: A central office 1 and a terminating device 2 installed near the subscriber side modem device 31 are connected via an optical fiber cable 4 and joined to the terminating device 2. In a digital telephone transmission device connected to the modem device 31 via the electric wire cable 5,
The digital processing unit 111 of the configuration of the office-side modem device 11 is arranged in the central station 1, and the A / D converter 113 and D / D
Analog front end unit 11 including A converter 114
2 was constructed.

[0011] Claim 2: In the digital telephone transmission device according to claim 1, the station side modem 11
The subscriber-side modem device 31 constitutes a digital telephone transmission device which is a modem device compatible with xDSL technology. Further, in the digital telephone transmission apparatus according to any one of claims 1 and 2, the central station 1
Is an optical-to-electrical converter E / O connected to the digital processing unit 111 of the station side modem device 11 via the multiplexer 12.
The terminating device 2 has an optical-to-electrical converter 23 connected to the analog front-end unit 112 via the multiplexer 22, and connects the optical-to-electrical converters 13 and 23 via the optical fiber cable 4. A connected digital telephone transmission device was constructed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 shows an optical fiber x according to the present invention.
FIG. 2 is a diagram illustrating a DSL transmission device. The xDSL technology-compatible station-side modem device 11 converts the
A / D converter 1 for analog-to-digital conversion of signal 1 and signal
13 and a D / A converter 1 for digital-to-analog conversion
And an analog front-end unit 112 composed of fourteen. The digital processing center is arranged in the central station 1, and the analog front end unit 112 is arranged in the terminal device 2 installed on a telephone pole or the like near the subscriber side modem unit 31 and connected to the end of the optical fiber cable 4. That is,
The central office 1 is a digital processing unit 11 of the office-side modem device 11.
1 and the modem unit 11 via the multiplexer 12
-Electric converter 1 connected to digital processing unit 111
Three. The terminating device 2 installed near the subscriber-side modem device 31 compatible with the xDSL technology is connected to the centralized station 1 via the optical fiber cable 4 and is connected to the optical network.
An electrical converter 23, and A / D converters 113 and D / D converters connected to the optical-electrical converter 23 via the multiplexer 22.
Analog front end unit 112 including A converter 114
And The termination device 2 is connected to the subscriber-side modem device 31 via the electric wire cable 5.

The analog electric signal to be transmitted to the subscriber 3 via the centralized station 1 is transmitted to the station side modem 11
Is converted into a digital signal by the digital processing unit 111 of the optical-to-electrical converter 1 through the multiplexer 12.
3 and converted into a digital optical signal. This digital optical signal is output to the optical fiber cable 4 and transmitted to the terminating device 2 disposed near the subscriber side modem device 31 via the optical fiber cable. The digital optical signal transmitted to the termination device 2 is input to the optical-electrical converter 23 and converted into a digital electric signal. The converted digital electric signal is input to the D / A converter 114 of the analog front-end unit 112 via the multiplexer 22 and is converted into an analog electric signal, which is transmitted to the subscriber-side modem device 31 via the electric cable 5. Is done.

Conversely, an analog electric signal to be transmitted to the central office 1 via the subscriber side modem unit 31 is transmitted to the A / D converter 113 of the analog front end unit 112 of the terminal unit 2 via the electric cable 5. And is converted into a digital electric signal. This digital electric signal is input to the optical-electrical converter 23 via the multiplexer 22, and is converted into a digital optical signal. The digital optical signal is output to the optical fiber cable 4 and transmitted and input to the optical-electrical converter 26 of the central station 1 via the optical fiber cable 4 to be converted into a digital electric signal. The converted digital electric signal is input to the digital processing unit 111 of the station side modem device 11 via the multiplexer 12, where it is subjected to digital signal processing.

[0015]

As described above, according to the present invention, the digital processing unit 111 and the A / D converter 113 for analog-to-digital conversion of a signal and the D / A conversion for digital-to-analog conversion are provided. Only the digital processing section 111 of the analog front end section 112 including the converter 114 is arranged in the central station 1, while the analog front end section 112 including the A / D converter 113 and the D / A converter 114 is connected to the subscriber side. It is attached to a telephone pole or other members near the modem device 31 and is fixed to the terminal device 2 connected to the end of the optical fiber cable 4. As a result, the terminating devices 2 scattered at many locations apart from the central station 1 are provided with the A / D converter 113 and the D / A converter 11 which are the minimum circuits in the configuration of the station side modem device 11.
Since only four devices need to be accommodated, the device can be easily accommodated in the terminal device 2 having a severely limited space for accommodating the devices. Since the A / D converter 113 and the D / A converter 114 have very little risk of failure or aging, there is almost no need to adopt new standards and make design changes corresponding to higher speeds. The difficulty of maintenance of the terminal devices 2 scattered in many places is eliminated. In the case of design changes to accommodate the adoption of new standards and higher speeds,
It can be easily handled only by updating the configuration of the central station 1.

[Brief description of the drawings]

FIG. 1 illustrates an embodiment.

FIG. 2 is a diagram generally illustrating a conventional example of xDSL.

FIG. 3 is a diagram illustrating a conventional example of xDSL including an optical fiber cable.

FIG. 4 is a view for explaining another conventional example of xDSL including an optical fiber cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Centralized station 11 Station side modem device 111 Digital processing unit 112 Analog front end unit 113 A / D converter 114 D / A converter 12 Multiplexer 13 Optical-electrical converter 2 Termination device 22 Multiplexer 23 Optical-electrical converter 3 Subscription Party 31 subscriber side modem device 4 optical fiber cable 5 electric wire cable

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04Q 3/42 104 H04B 9/00 BF Term (Reference) 5K002 AA05 DA03 DA05 DA08 DA12 FA01 GA02 5K027 AA10 CC00 CC01 5K049 BB09 BB10 BB22 BB23 BB26 CC00 CC08 5K050 BB06 BB12 BB14 BB17 DD27 DD30 EE25 FF14 5K051 AA03 BB02 DD07 DD09 DD12 DD13 DD14 EE04 JJ02

Claims (3)

[Claims] 1. A central office and a terminating device installed near a subscriber-side modem device are connected via an optical fiber cable, and the terminating device and the subscriber-side modem device are connected via an electric wire cable. In a digital telephone transmission device to be connected, a digital processing unit of the configuration of the office-side modem device is arranged at the central office, and an A / D converter and a D / A converter of the configuration of the office-side modem device are arranged at the termination device. A digital telephone transmission device comprising an analog front-end unit comprising: 2. The digital telephone transmission device according to claim 1, wherein the station-side modem device and the subscriber-side modem device are xDSL technology-compatible modem devices. 3. An optical-to-electrical converter according to claim 1, wherein said centralized station is connected to a digital processing section of a station side modem via a multiplexer. Wherein the terminating device has an optical-to-electrical converter connected to the analog front-end section via a multiplexer, and both optical-to-electrical converters are connected via an optical fiber cable. Digital telephone transmission equipment.