Arrangement for data transmission utilizing telephone network

Details Arrangement for data transmission utilizing telephone network Arrangement for data transmission utilizing telephone network

1998-03-19

2001-05-22

Le, Huyen (Department: 2743)

Telephonic communications

Telephone line or system combined with diverse electrical...

Having transmission of a digital message signal over a...

C379S090010, C379S093310

Reexamination Certificate

active

06236719

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an arrangement for data transmission which utilizes a telephone network connection between modems for data terminal equipment that is connected to a telephone switching center via telephone subscriber lines.
2. Description of the Related Art
In a telephone network that is utilized for data communications, modems (which include modulators and demodulators) provide a data transmission means that are arranged as a link for adapting between telephone voice paths and data terminal equipment and that serve the purpose of converting the digital signals supplied by the data terminal equipment into line signals which are advantageous for data transmission and which correspond to the electrical conditions for analog telephone connections or which undertake a back-conversion of such line signals into digital signals.
Different modulation methods, such as frequency modulation, phase-difference modulation and quadrature amplitude modulation, are applied in this context (see, for example, Handwörterbuch des elektrischen Fernmeldewesens, published on commission of the Bundesministerium für das Post- und Fernmeldewesen).
There are a multitude of different modem protocols for modem connections including, for example, those specified by the ITU-T (formerly CCITT) in what is referred to as the V-series.
FIG. 1
of the drawings shows how data transmission was previously sequenced over the telephone network.
Data signals which are derived from data terminal equipment, for example a personal computer PC
1
, are converted into line signals in a modulator MOD
1
and are transmitted to a telephone switching center LE
1
via a subscriber line TL
1
, which mainly serves for transmitting voice signals from and to telephone terminal equipment. In a subscriber line circuit TSCH
1
to which the subscriber line TL
1
is connected, the line signals experience the same handling as voice signals, namely a band limitation to 300 through 3400 Hz, an analog-to-digital conversion, a compression according to the A-law or the &mgr;-law, and are ultimately transmitted via a PCM link PCM of the telephone network SPN, to which the switching center LE
1
also belongs, to a destination switching center LE
2
of the telephone network to which the other data terminal equipment that is in the form of the personal computer PC
2
for the connection under consideration is connected. In the subscriber line circuit TSCH
2
of the destination switching center LE
2
, the transmitted data experience a corresponding back-conversion, namely an A-law or &mgr;-law expansion and a digital-to-analog conversion, before they are transmitted via the telephone subscriber line TL
2
to the modem MOD
2
, in order to proceed therefrom to the data terminal equipment PC
2
after conversion into digital signals.
Except for the data terminal equipment, the system parts mentioned in conjunction with the described data signal transmission, which mainly serve for voice signal transmission between telephone terminal equipment such as the illustrated terminal equipment Tel
1
and Tel
2
, are accordingly optimized for the voice signal transmission and therefore have a limiting effect for the data transmission in view of the transmission rate and the transmission bandwidth. Highly complex modulation methods for the digital data are utilized in order to achieve an enhancement of the obtainable data rates, this, of course, resulting in correspondingly increased outlay.
Given the above-described, known way of sequencing data transmissions using the telephone network, there is a direct communication of the subscribers—as in voice signal connections—with one another. In this case, the subscribers are the modems. This requires that the subscribers must “understand one another”, i.e. that the same modem protocol must be employed at both modems at the two terminal equipment sides. A further demand arises when modem protocols are reformulated since these new protocols must also cover previous modem protocols so that modems which are already installed can continue to be employed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an arrangement for data transmission utilizing the telephone network between modems for data terminal equipment connected to a telephone switching center via analog telephone subscriber lines to such effect that such modem connections are possible without the aforementioned restrictions.
Given the present inventive arrangement, accordingly, a modem that works according to the same modem protocol as the modem connected to the respective telephone subscriber line at the subscriber side is arranged in the telephone switching centers at the interfaces to affected telephone subscriber lines, i.e. those that set up a connection to the modem of a data terminal equipment. This thus means that, given a data connection between two modems for data terminal equipment at the terminal equipment side, these modems of the terminal equipment side no longer have to communicate directly with one another but need only communicate with the modem located in the switching center. The modem protocols that are applied given such a communication and, in particular, the type of encoding method employed are thus only dependent on the properties of the transmission link between the terminal equipment modem and the switching center. This enables the definition of modem protocols that cover all previous standards and that are also in the position to transmit significantly higher data rates (such as data rates >>64 kbit/s).
According to a further development of the invention, the exchange-side modems are placed as close as possible to the interface to the telephone subscriber line. All voice-signal-specific equipment in the entry region of the switching center thus no longer have to be traversed, this, as indicated, having led to limitations under the previous practice. For example, the compression and expansion according to the A-law or &mgr;-law provided for voice signals can be avoided by the present invention.
According to another development of the invention, the exchange-side modems are configured for optional operation according to different modem protocols, preferably according to all known protocols that are in practice, so that communication with any of the types of modems which may occur at the terminal equipment side is possible without further ado.
According to yet another development, the exchange-side modems are integrated in subscriber-individual physical subscriber line units or subscriber-group-individual subscriber line modules for the connection of the telephone subscriber lines.
According to yet a further development, the physical subscriber line units comprise a terminal to a data network in this case in addition to their terminal to the telephone switching center, whereby these terminals are alternatively activated for the data signals to be transmitted between the data terminal equipment. Given this construction, a subscriber equipped with an arbitrary, commercially available modem at the terminal equipment side can be conducted directly into the data network via the subscriber line of the switching center or its data network terminal. Connections to the data network, which often last for a relatively long period of time, for example, connections using Internet applications, are thus prevented from burdening the parts of the telephone network that are not individual to the subscriber, beyond the connection setup and the connection shutdown.
In another aspect, the exchange-side modems are realized by employment of a digital processor system, for example a signal processor or microprocessor. The respective, selective modem protocol behavior can then be achieved in a simple way by loading appropriate software or by replacing or regrouping corresponding function blocks.
For realizing the modems in the case of the presence of subscriber line modules, it is provided that a signal processor pool be formed that comprises fewer signal pro

Affiliated with

Also associated with

Rating

Arrangement for data transmission utilizing telephone network does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Arrangement for data transmission utilizing telephone network, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arrangement for data transmission utilizing telephone network will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2551417