HDSL (English: H igh D ata Rate Digital S subscriber L ine) - high-speed digital subscriber line.

This is the first technology for high-speed data transmission (HD) over twisted copper pairs of telephone cables using high frequencies. It was developed in the USA in the late 80s as a higher-speed, synchronous technology for organizing transmission channels not only for data, but also for voice channels, using /.

HDSL can operate at either T1 (1.544 Mbps) or E1 (2 Mbps) speeds. Lower speeds are served using 64 Kbps channels within a T1/E1 package.

This is commonly called a T1/E1 stream, and is used to provide low-speed links to users. In such cases, the channel speed will be full (T1/E1), but the subscriber will receive only a limited speed of 64 Kbit/s (or several 64 Kbit/s) on its part.

Due to the need to provide symmetrical PD, the maximum PD speed is only supported at a distance of no more than 4.5 km when using one or two twisted cable pairs. PD over long distances is possible, provided that regenerators are used. The data is encoded using the 2B1Q method (two bits (2V) into one of four voltage levels (1Q)), using duplex, and therefore echo cancellation techniques.

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See what "HDSL" is in other dictionaries:

HDSL- es el acrónimo de High bit rate Digital Subscriber Line o Línea de abonado digital de alta velocidad binaria. Ésta es una más de las tecnologías de la familia DSL, las cuales han permitdo la utilización del clásico bucle de abonado telefónico,… … Enciclopedia Universal

HDSL- UK [ˌeɪtʃ diː es ˈel] US [ˌeɪtʃ di es ˈel] noun computing High Data Rate Digital Subscriber Line: a … Useful english dictionary

HDSL- , DSL … Universal-Lexikon

HDSL- (High bit rate DSL) digital symmetrical phone line that transmits data in wideband at equal rates in both directions… English contemporary dictionary

HDSL- High Data Rate Digital Subscriber Line (HDSL) war die erste DSL Technologie, die ein höheres Frequenzspektrum der Kupferdoppelader nutzte. Sie wurde zunächst in den USA entwickelt. In den USA gibt es Leitungen für 1.544 kbit/s (so genannte T1… … Deutsch Wikipedia

HDSL- High data rate digital subscriber line HDSL (pour High bit rate Digital Subscriber Line soit Ligne d abonné numérique à haut débit en français) est une technologie xDSL utilisant un code en ligne “2B1Q”, (famille d ADSL). Sommaire 1… … Wikipédia en Français

HDSL- UK [ˌeɪtʃ diː es ˈel] / US [ˌeɪtʃ dɪ es ˈel] noun Word forms HDSL: singular HDSL plural HDSLs computing High Data Rate Digital Subscriber Line: a dsl that works at a fast speed … English dictionary

HDSL- didelio pralaidumo skaitmeninė abonento linija statusas T sritis informatika apibrėžtis Skaitmeninė abonento linija, kurios pralaidumas didesnis, bet ilgis žymiai trumpesnis, negu įprastos. Gali būti simetrinė arba asimetrinė. atitikmenys: engl… Enciklopedinis kompiuterijos žodynas

HDSL- High (bit rate) Digital Subscriber Line (Academic & Science » Electronics) ** High data rate Digital Subscriber Line (Computing » Networking) * High bit rate Digital Subscriber Loop (Computing » General) * High (Data Rate) Subscriber Line… … Abbreviations dictionary

HDSL- High rate/High speed Digital Subscriber Link (s. HSDL) … Acronyms

HDSL ( High bit-rate DSL) an established high-speed, high-capacity two-way data transmission technology over twisted pair cable without repeaters, providing a fixed speed of 1.544 or 2.048 Mbit/s (in Europe) in both directions.

Adaptive HDSL options allow you to customize the transfer speed.
HDSL (G.991.1 standard) is considered one of the most mature xDSL technologies.

As a rule, it requires a four-wire subscriber line, it implements symmetrical duplex data transmission over one copper pair over a distance of about 4.5–6.5 km over UTP category 3 cable, uses 2B1Q line coding or, in more modern equipment, CAP.

HDSL is often used to implement data transmission channels at T1/E1 speed over telephone lines, to organize inter-station connections of digital or (together with multiplexers) analogue PBXs, to connect corporate PBXs, to multiplex subscriber lines and to organize subscriber outreach (together with TDM multiplexers), and also providing access to high-speed fiber-optic paths SDH or PDH, connecting local networks or high-speed access to data networks, connecting switching nodes and base radio stations of cellular communication networks.

HDSL provides high speed Internet access and is capable of supporting real-time network applications (Internet telephony, etc.).

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1 . Concepttechnologiesx- DSL

Over the past 120 years, millions of kilometers of telecommunications lines made from good old copper have been installed around the world. The advent of the digital era, fiber optics, seemed to put an end to copper cable. However, life decreed differently. DSL technologies, developed to provide high-speed digital communications over existing copper lines, have proven that buried cable is a valuable asset that is far from time to be scrapped.

In Fig. shows the evolution of transmission speed over copper cable lines from Morse code (10 bit/s) to VDSL technologies (51 Mbit/s). xDSL technologies (DSL - Digital Subscriber Loop) began their development in the 70s with the creation of devices. access BR (Basic Rate) ISDN (160 kbit/s). These technologies, which promise mass introduction of VDSL equipment in the near future, make it possible to achieve transmission speeds on copper cable that were previously only available through fiber-optic lines. With the development of the xDSL concept, the ideology of the development of communication networks has changed significantly. Previously, it was widely believed that bringing “digital technology into every home” was possible only through the mass introduction of optical cables. Currently, after practical testing of xDSL technologies, especially HDSL (see below), telecom operators have confidence that the existing network of copper communication cables will remain for a long time the basis on which the entire telecommunications infrastructure is built.

The first of xDSL is ISDN U-interface technology, which provides full-duplex (both ways) transmission at 160 kbps over a single twisted pair cable. This technology is widespread and, in addition to ISDN networks, is used to create equipment for multiplexing subscriber lines and modems over a limited distance (short-range).

Picture 1 - Increase in digital transmission speed over copper communication lines

The next technology in the xDSL series (and the most common currently) is HDSL (High-bit-rate Digital Subscriber Loop). HDSL technology provides full duplex communication at a speed of 2048 kbps. Two or three cable pairs are used for transmission. A further development of HDSL technology was the emergence of symmetrical high-speed digital subscriber line devices operating over one pair - SDSL (Single Pair Symmetrical Digital Subscriber Loop).

In recent years, higher speed xDSL technologies have also been developed, such as ADSL and VDSL. ADSL (Asymmetric DSL) technology provides transmission of up to 8 Mbit/s in the direction “from the network to the subscriber” and up to 1 Mbit/s in the direction “from the subscriber to the network” and promises to be very promising for access to the Internet. At the same time, ADSL is unlikely to find widespread use in telephony, where, as a rule, symmetrical duplex transmission is required. The use of ADSL as a means of access is currently limited by the limited capacity of backbone networks. For example, an Internet provider with a backbone network capacity of 155 Mbit/s (STM-1) will be able to connect only about 20 subscribers (155/8) at a speed of 8 Mbit/s.

Regarding technology VDSL(Very High-bit-rate Digital Subscriber Loop) 4 then it has not yet left the laboratories, although a number of manufacturers announced the appearance of equipment using VDSL in 1998.

All xDSL technologies were initially considered as subscriber access technologies (hence the name), intended for use on subscriber lines, that is, copper cable pairs laid from the telephone exchange to the subscriber's location. In reality (see below), the scope of application of xDSL technologies is much wider. For example, the leading manufacturer of xDSL equipment in the United States, PairGain Technologies, has achieved the largest volume of deliveries of HDSL systems for the task of upgrading inter-exchange digital trunk lines with transmission speed 1.5 Mbit/s- T According to the leading European manufacturer of xDSL systems, Schmid Yelecom Alger (Switzerland), the modernization of existing and the organization of new E1 paths for interexchange communication (functional analogue of T1 according to the European standard) remains one of the main applications of HDSL systems in Europe. The experience of introducing HDSL equipment in Russia also speaks to this.

However, to better explain the idea of developing HDSL technology and the typical distance, or operating range of the equipment, we present the typical parameters of subscriber lines. According to experts, on urban telephone networks in Russia the average length of subscriber lines (SL) is 1280 m (with a coefficient of variation of 0.59), while 100% of subscriber lines do not exceed 5 km in length. According to other data (Schmid Telecom AG), taking into account rural and suburban networks, more than 60% of AL in Eastern European countries do not exceed 6 km in length, and 95% are within 2 km. HDSL technology, originally intended for the “digitalization” of subscriber lines, was developed in such a way as to ensure operation on the vast majority of existing telephone lines. Therefore, the “basic range” for HDSL systems is 5-6 km (per pair with a core diameter of 0.4-0.5 mm). Since subscriber lines are often carried out with a composite cable, sections of which have different cross-sections of cores (from 0.35 mm to 0.9 mm), xDSL technologies must be operational on lines of the most “complex” topologies. And finally, since a cable usually has several tens (or even hundreds) of cores, xDSL equipment must coexist with equipment operating on adjacent pairs, be it another xDSL system, ISDN, or a regular analog telephone. such complex tasks, and will be discussed below.

2 . Coding technologies used inHDSL

The most widely used technology currently in the xDSL series (with the exception of BR ISDN) is HDSL technology, so it will be discussed in more detail. The main idea of HDSL technology is the use of existing electrical (most often with copper conductors) cable for symmetrical duplex non-regenerator transmission of 2 Mbit/s digital streams over long distances. HDSL equipment is applicable to work over any type of cable - symmetrical city (TPP and similar), trunk (KSPP, ZKP) and even (after some processing of linear matching units) coaxial.

The main factors influencing the quality of HDSL equipment are the communication line parameters . Let us recall the key ones for xDSL technologies:

Signal attenuation . Signal attenuation in a cable line depends on the type of cable, its length and signal frequency. The longer the line and the higher the signal frequency, the higher the attenuation.

2. Nonlinearity of frequency response. Typically, the cable line is a low-pass filter.

Crosstalk at the near and far ends (FEXT, NEXT).

4. Radio frequency interference.

5. Group delay time . The speed of signal propagation in the cable depends on its frequency, thus, even with a uniform frequency response, the shape of the pulse during transmission is distorted.

The basis of HDSL equipment is a linear path, that is, a method of encoding (or modulating) a digital stream for transmission over a copper line. HDSL technology involves the use of two linear coding technologies - 2B1Q (2 binary, 1 quartenary) and CAP (Carrierless Amplitude and Phase Modulation). Both technologies are based on digital processing of transmitted and received signals by a so-called signal processor and have a number of common principles. Thus, to reduce the frequency of the linear signal, and therefore increase the operating range, adaptive echo cancellation is used in HDSL technology. Its essence is that reception and transmission are carried out in the same spectral range, and the signals are separated by a microprocessor. The HDSL modem receiver subtracts from the linear signal the signal of its own transmitter and its echo (the signal reflected from the far end of the cable or from the junction of the composite cable). The HDSL system is configured to the parameters of each line automatically, the equipment dynamically adapts to the parameters of each cable, so when installing the equipment or moving it from one site to another, no manual settings or adjustments are required.

The use of echo cancellation and reduction in the frequency of the linear signal made it possible to transmit in both directions not only over one pair, but also in one cable, which is also a key advantage of HDSL technology over the previously used HDB3 or AMI line coding methods. Let us recall that the T1 or E1 paths built before the advent of DSL technologies, in addition to installing many linear regenerators (every 1000-1500 m), required the laying of two cables, in one of which all pairs were used for transmission, and in the other for reception.

3 . Technology 2B1Q

Let's take a closer look at each of the HDSL encoding methods. The 2B1Q technology, developed first, remains widespread in Western European countries and the USA. It was originally used in ISDN networks to transmit a 144 kbit/s stream (BR ISDN), and was later upgraded to transmit higher-speed streams. The 2B1Q code is a modulated signal with 4 levels, that is, 2 bits of information (4 code states) are transmitted at each time. The spectrum of the linear signal is symmetrical and quite high-frequency (see Fig. 4.2). Low-frequency and constant components are also present. Let's consider how various factors influence the transmission of the 2B1Q code.

In urban conditions, a large amount of low-frequency interference is created, for example, when starting up powerful electrical machines (metro, trams, etc.), electric welding, in addition, a large amount of impulse noise is created in communication cables (dialling, transmitting alarm signals, etc.). d.). LSI sets that implement 2B1Q technology provide fairly sophisticated methods for correcting distortions in the low-frequency region of the spectrum and satisfactory transmission quality. However, 2B1Q coding still remains sensitive to distortion, since the signal has a constant component.

The presence of a large frequency spread in the spectrum of the 2B1Q signal makes it necessary to solve problems associated with the group delay. Microprocessor processing helps solve this problem, although the signal processing algorithm becomes significantly more complicated.

Figure 2 - 2B1Q Technology

The spectrum of the 2B1Q code contains high-frequency components, the maximum energy is transmitted in the first “lobe”, its width is proportional to the speed on the line. The signal attenuation in a cable increases with increasing frequency, so depending on the required range, one of three line signal speeds is used (784 kbit/s, 1168 kbit/s or 2320 kbit/s). 2B1Q technology involves the use of one, two or three pairs of copper cable to transmit a 2 Mbit/s stream. Each of the pairs transmits part of the flow (see Fig. 4.2) at the above-mentioned speeds. The greatest operating range is achieved when using three pairs (about 4 km along a 0.4 mm core), the shortest - when operating on one pair (less than 2 km). Due to the fact that the operating distance of HDSL systems (2B1Q encoding) using 1 pair does not satisfy the basic range requirements, such systems are not widely used. Systems operating on three pairs are still quite widely used, but are gradually being replaced by systems using ATS technology and providing the same range on two pairs. The most widespread systems with 2B1Q coding are systems operating in two pairs. The operating range of such systems (about 3 km along a 0.4 mm core) provides the vast majority of access tasks in Western Europe and the USA, where the length of the line in 80% of cases (data from Schmid Telecom AG) does not exceed 3 km.

Radio frequency interference has a major impact on transmission. Radio transmissions in the long and medium wave ranges, the operation of powerful radio relay lines cause interference on the cable line and interfere with the transmission of the 2B1Q code if they have matching parts of the spectrum. This factor has a particularly negative effect when using HDSL equipment to connect studios and radio transmission centers, or when installing equipment indoors or in close proximity to radio and television centers.

According to most experts, from a technical point of view, 2B1Q technology is somewhat inferior to the later linear coding technology - ATS. However, a large amount of equipment using 2B1Q is still produced around the world. Why? The answer is quite obvious. Firstly, the length of subscriber lines in the US and Western. Europe, as a rule, is quite small, so the range of the 2B1Q is quite sufficient. The cable quality in the above-mentioned regions is also quite high, which reduces the influence of various interfering factors. Secondly, an important advantage of the 2B1Q technology is its low cost. About ten large LSI manufacturers supply comprehensive solutions for creating HDSL equipment using 2B1Q technology. The presence of competition, naturally, has a positive effect on the price of microcircuits and finished transceiver modules. According to foreign experts, 2B1Q technology is becoming more and more “accessible”, that is, a large number of companies, even those not specializing in the production of xDSL equipment, have the opportunity to quickly and cheaply develop their own HDSL device or unit using ready-made solutions (sometimes entire HDSL modules ) from LSI suppliers such as METALINK, BROOKTREE (ROCKWELL), PAIRGAIN TECHNOLOGIES, etc.

As for the countries of Eastern Europe, South America, Asia, due to the longer length of subscriber and connecting lines, as a rule, lower quality of laid cables, HDSL systems based on ATS technology are in great demand

(Carrierless Amplitude and Phase Modulation) - amplitude-phase modulation without carrier transmission. The developer of the technology, the GlobeSpan company (part of the former AT&T), set itself the goal of creating a narrowband linear coding technology that is not sensitive to most external interference, which, as the experience of implementing HDSL systems based on ATS technology in the United States and Russia shows, has been quite successful.

4 . ATS technology

ACS modulation combines the latest achievements of modulation technology and microelectronics. The modulation diagram of the ATS signal resembles the signal diagram of modems for telephone channels operating using the V.32 or V.34 protocols. The carrier frequency is modulated in amplitude and phase, creating a code space with 64 or 128 states. In this case, by transmitting into the line, the carrier itself, which does not transmit information, but contains the greatest energy, is “cut out” from the signal and then restored by the receiver’s microprocessor. According to the 64-position modulation diagram, the CAP-64 signal transmits 6 bits of information at each moment in time, that is, 16 times more compared to 2B1Q. CAP-128 modulation, used in SDSL systems (2 Mbit/s over one pair), has a 128-position modulation diagram and, accordingly, transmits 7 bits per clock cycle. The result of increasing the information content of a linear signal is a significant reduction in the signal frequency and spectrum width, which, in turn, made it possible to avoid spectrum ranges that are most susceptible to various types of interference and distortion. In Fig. Figure 4.3 shows the spectrum and modulation diagram of the ATS signal.

Figure 3 - ATS technology

To explain the advantages of ACS modulation in Fig. 4.4 superimposes the spectra of signals with the code HDB3 (a technology previously used to create E1 lines, in particular used in linear paths of PCM-30 type systems), 2B1Q and ACS.

From a comparative analysis of the spectra, the positive features of HDSL systems based on ACS modulation are visible.

Maximum operating range of the equipment. The attenuation in the cable is proportional to the frequency of the signal, so an ATS signal, the spectrum of which does not have components above 260 kHz, propagates over a greater distance than a signal with code 2B1Q or HD6 Under the conditions that the output power in HDSL systems is limited by standards (+13.5 dB) , and increasing the sensitivity of the receiver above -43 dB is not possible due to noise, reducing the frequency of the linear signal leads to a gain in operating range of HDSL systems based on ATS technology compared to 2B1Q. For systems operating on two pairs (see Table 4.1 below), this gain is 15-20% (for a 0.4-0.5 mm core), for SDSL systems (that is, operating on one pair) - 30- 40%. If we compare the transmission range (without regenerators) achieved in HDSL systems based on ATS technology with the operating range of the PCM-30 linear path (HDB-3), the gain will be 350-400%.

Figure 4. Spectra of HDB3, 2B1Q, CAP signals

2. High noise immunity and insensitivity to group timeeno delay. Due to the absence of high-frequency (above 260 kHz) and low-frequency components (below 40 kHz) in the spectrum, ACS technology is not sensitive to high-frequency interference (crosstalk, radio interference) and impulse noise, as well as to low-frequency interference and distortion, for example, during startup powerful electrical machines (railway, metro) or electric welding. Since the spectral width is only 200 kHz, effects caused by group delay do not occur.

Minimum level of interference and interference to neighboring pairs. The ATS signal does not cause interference (mutual influence) and interference in the spectrum of a conventional (analog) telephone signal due to the absence of components below 4 kHz in the spectrum. This removes restrictions on the use of adjacent pairs for conventional (analog) subscriber or inter-exchange connections.

4. Compatibility with compaction equipment operating in neighboring areasAram. Most analog multiplexing systems for subscriber and trunk lines use spectrum up to 1 MHz. Systems with ACS modulation can cause interference on frequency channels in the range of 40-260 kHz, but the remaining channels are not affected in any way; therefore, it is possible to use HDSL ATS equipment in the same cable with analog compression equipment. HDSL systems with 2B1Q modulation cause interference on virtually all frequency channels of analog multiplexing systems that load adjacent pairs, therefore, as a rule, they cannot be used in the same cable with analog multiplexing equipment.

DIGITAL COMPACTING SYSTEMS (DCS) OF SUBSCRIBER LINES

Selecting DSL Technology

Having conducted an analytical review of xDSL technologies, we can characterize that the choice of DSL technology is determined by:

a) the required bandwidth.

b) distance from the telephone exchange.

c) the type of equipment installed by the service provider at the telephone exchange.

Table 4.1 Main comparative characteristics of xDSL technologies

Having carried out a comparative analysis of the main characteristics of xDSL technologies (Table 4.1), we believe that in order to solve the problems set before us, we need to use equipment made on the basis of HDSL technology, which will provide us with a transmission range of up to 4.5 - 5 kilometers and a transmission speed of up to 1.5 mbit/s

HDSL systems with CAP-64/CAP-128 modulation can be used to organize flows up to 2 Mbit/s over two pairs, as inter-office trunk lines (for example, WATSON 3 equipment uses CAP-64 and operates over two pairs).

Systems with ACS modulation can cause interference on frequency channels in the range of 40-260 kHz, but the remaining channels are not affected in any way, therefore, it is possible to use HDSL ATS equipment in the same cable with analog compression equipment. HDSL systems with 2B1Q modulation cause interference on virtually all frequency channels of analog multiplexing systems that load adjacent pairs, therefore, as a rule, they cannot be used in the same cable with analog multiplexing equipment.

HDSL systems with 2B1Q modulation are widely used to compress subscriber lines of city telephone networks, mainly consisting of low-frequency cables of the TPP type with copper conductors, polyethylene insulation and sheath.

We choose equipment made on the basis of HDSL technology and providing a transmission range of up to 4.5 - 5 kilometers at a transmission speed of up to 1.5 Mbit/s with a 2B1Q line code.

In accordance with the above, the question arose of choosing specific systems for digital subscriber multiplexing PCM with the presence of 2, 4, 11 channels.

HDSL equipment in subscriber access networks

Equipment for digital multiplexing of subscriber lines RSM

Digital multiplexing systems for subscriber lines RSM are designed for use in a substation network in order to save copper cable cores, and represent an effective way to increase number capacity. Savings are achieved by increasing subscriber capacity by compacting existing trunk and distribution cables.

PCM systems provide direct and independent telephone connections for two, four, six, eight, ten, eleven, twelve, sixteen and eighteen subscribers over one physical line. Simultaneously with digital multiplexing, the quality of communication is significantly improved, background noise and cross-talk are eliminated.

The use of PCM makes it possible to rationally use existing cable lines, reduce the time for developing a telephone network (especially for groups of remote subscribers) and reduce material costs for cable products. As terminal subscriber terminals, it is possible to connect telephones with pulse and tone dialing, radiotelephones, smart card payphones, traditional analogue payphones with line reversal, faxes of group “3” (9600 kBit/s).

Subscriber line multiplexing systems allow you to organize data transmission over a multiplexed channel using modems. Currently used modems use standard analog-to-digital conversion protocols, which allows data transmission at a speed of 26.4 kBit/s.

It should be noted that telephone sets may be of the old type with a carbon microphone and a rotary dialer.

Digital multiplexing of subscriber lines PCM is produced by more than ten telecommunications equipment manufacturers. PCM systems from Alcatel, Tadiran, ECI, Intracom, Elcon Systemtechnik, Ericsson, Telspec Europe Limited, Apsun Technology have been tested on the Kazakhstan market. In order to determine the PCM systems that best meet “our” technical conditions, in 1998 the company OJSC Kazakhtelecom held a tender. Three companies received the right to supply PCM systems on the networks of OJSC Kazakhtelecom: Alcatel, ECI, Elcon Systemtechnik.

Telspec Europe Limited, although it did not receive the right to supply equipment to Kazakhstan, made a serious bid for the future. Therefore, we will consider this company when choosing RSM equipment.

The choice of compaction system is carried out based on specific conditions, optimizing the costs of connecting subscriber terminals, taking into account development and modernization.

On urban networks, the most common are 4-channel systems. At the same time, not only distribution lines, but also trunk lines are noticeably freed up, which makes it possible to flexibly build an access network to subscribers over a large area. Make maximum use of the available capacities of station and line structures.

The use of PCM 11 systems is most beneficial in private sector areas and in suburban areas with a poorly developed cable network. And also when new telephone exchanges are put into operation with telephone installation in multi-storey new buildings located within a radius of up to 3 kilometers from the telephone exchange.

PCM 2 systems are used in cases where there is a shortage of lines and separate installations of terminals are required in places with a high degree of telephone coverage. If the subscriber wishes, install an additional terminal (telephone) with an independent number when expanding the payphone network.

When replacing mechanical PBXs with electronic ones, the question arises of providing 30% of blocked subscribers with independent numbers. In this case, the PCM 2 system is ideal.

In rural settlements with a small number of subscribers and where the power supply is often interrupted for a long time, it is especially advantageous to organize communications on the network using 4.11 channel PCM systems.

As a temporary measure, in such populated areas it is possible to mothball the terminal station equipment, and connect existing subscribers using RSM equipment to district-level stations or stations with a provided power supply. In some cases, when the PBX equipment is worn out, it is advisable to close the station and switch subscribers using PCM to an existing higher-level station.

In such settlements, to ensure the possibility of providing telecommunications services to a wide range of people who do not have telephones, it is possible to install a payphone(s) connected to the district automatic telephone exchange via one of the RSM channels.

Structural diagrams of organizing communications using RSM equipment are given in Appendix B.

Description of Alcatel PCM systems

Alcatel equipment includes systems PCM2, 4, 11, 16. Let us dwell in more detail on the PCM 11 system.

RSM 11 is a digital multi-channel transmission system that allows you to organize eleven independent channels with a capacity of 64 kBit/s each, using one twisted copper pair. The transmission technology used is HDSL, with a transmission speed of 784 kBit/s. The RSM 11 system consists of a station unit RSM 11 CO, installed on the telephone exchange, and a subscriber unit RSM 11 RU, installed at the subscriber. Up to eight RSM 11 CO devices can be installed in one universal cassette. The range of the RSM 11 system can be doubled by using an intermediate regenerator.

The range of the RSM 11 system depending on the cable diameter is shown in Table 4.2

Table 4.2 Operating range of the RSM11 system

Using a/v interfaces 1-11, the RSM 11CO station transmission system is connected to the two-wire interfaces of the telephone node. In addition to analog-to-digital and digital-to-analog conversion of speech information, incoming call voltages and charging pulses are recognized and processed, as well as outgoing signals are converted into loop codes. On the front side of the PCM11CO system there is an LED panel on which messages about intra-system failures of the subscriber and station units and information about operating modes are displayed.

The A/V interfaces of the PCM11 RU subscriber unit installed at the subscriber reproduce information transmitted via analog two-wire interfaces of the telephone exchange. The subscriber unit performs the functions of analog-to-digital and digital-to-analog conversion of speech information, as well as conversion of incoming loop code signals, supplying power to subscriber devices. Creates call voltages and tariff board pulses.

If the CLIP (Call Incoming Parameters Identification) service is provided by your network operator, it may be supported by the Alcatel PCM11 system. In this way, services that are usually only available on an ISDN network can also be provided on an analogue network. If the called subscriber is busy, he will receive a signal about an incoming additional call.

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HDSL technology Description of Alcatel PCM systems

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See what "HDSL" is in other dictionaries. HDSL technology Description of Alcatel PCM systems