Cable television network
A cable television network (formerly also known as broadband distribution network or coaxial network ) is an electrical cable network that connects private households and companies with service providers . It is a network of coaxial cables with several network levels , in which all lines are designed as insulated cables, mostly underground cables .
The original main purpose of the cable television network, known as the broadband cable network, is so-called cable television and the transmission of VHF radio . Nowadays, digital transmission methods such as DVB-C are used for this purpose . The expansion of a nationwide technical infrastructure for broadband distribution networks goes back to decisions made in the 1970s, particularly the recommendations of the Commission for the Expansion of Technical Communication Systems (KtK) from 1976.
By retrofitting bidirectional amplifiers to create a return channel capability, cable television networks have also increasingly been used for other services such as telephone calls and for connecting to the Internet since the turn of the millennium .
In Germany, cable television networks have been relocated since the 1980s by what was then Deutsche Bundespost , and later by Deutsche Telekom . Until 2003 these were sold to private companies as part of the liberalization of the telecommunications market .
In the narrower sense, a cable television network is a route-based broadband distribution network that was originally designed exclusively as a distribution medium.
In the narrower sense, the cable network itself usually consists of coaxial cables; The overall system of the cable network also includes amplifiers at a distance of approx. two kilometers as well as network terminations at both end points.
The cable headends can - but do not have to - be return channel capable ; Return channel capability is a prerequisite for two-way communication , for example if the cable network is to be used as a communication system at the same time as in the case of an Internet connection using a cable modem (see two-way cable network as an intermediate stage on the way to broadband communication ).
Cable networks in Europe
The Benelux countries already had the densest television cable network in 1997 . It reaches around 90 percent of all households ( Belgium : 98 percent, Netherlands : 92 percent, Luxembourg : 81.4 percent). In Denmark and Germany around 70 percent can receive cable TV. While there are 6,500 operators of cable services in Denmark, in Germany the monopoly of the Deutsche Bundespost was gradually capitalized from 1994 onwards .
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Data for Bulgaria , Greece , CIS and Italy are currently not available.
German cable television network
Expansion and connection density
In total, the German cable network for cable television consisted of 1200 individual networks with more than 4500 central amplifier points, around 240,000 amplifier points, 7.3 million signal transfer points and over 440,000 kilometers of copper coaxial cable. The cable network is divided into four network levels. The broadband distribution network laid and operated by the Deutsche Bundespost , later Deutsche Telekom , usually ends at a defined house transfer point (HÜP); this is usually in the basement of the building, where the private house distribution network ( network level 4 ) begins.
With a cabling rate of around 70 percent, Germany is in the middle of the field compared to other European countries. The number of 22 million connected households shows, however, that Germany has advanced to become the most important European market for cable reception; In 1994 the number of participants was only around 15 million and in 1986 it was 1.53 million.
On December 31, 1995, Deutsche Telekom reported 15.8 million users of cable connections; the cable density nationwide was 65.3 percent, the coverage level was 64.7 percent. Mecklenburg-Western Pomerania (75.1 percent) and Brandenburg (74.4 percent) had the highest connection density of all federal states , the highest level of coverage was achieved in Hamburg (99.4 percent) and Bremen (98.0 percent).
According to this, Saxony-Anhalt (56.9 percent) and Schleswig-Holstein (61.4 percent) have the lowest connection density, Thuringia (32.4 percent) and Saxony-Anhalt (27.6 percent) have the lowest coverage , followed by Brandenburg (39.5 percent) and Mecklenburg-Western Pomerania (39.6 percent). Most of the apartments connected to the television cable network are in North Rhine-Westphalia (3.7 million), Baden-Württemberg (2.0 million) and Bavaria (2.3 million).
At the beginning of 1997 the Monopoly Commission demanded that Deutsche Telekom should sell its cable network. The federal government rejected this demand in March 1997 on the grounds that such a forced sale would violate the Basic Law and company law .
After the prohibition of the nationwide joint digital cable television media platform of Deutsche Telekom, Bertelsmann and the Kirch Group for antitrust reasons by the EU Commission in 1998 and further pressure from the EU and national competition authorities, Telekom gradually sold its cable network from 2000 to 2003 in Form of regional sub-networks, which paved the way for the expansion of the return channel and the offer of cable telephony and cable internet ( triple play ) via the German cable network.
Frequency ranges used
Initially, only the VHF frequency range from 42 to 300 MHz was used to transmit radio and television . Later also the hyperband (302 to 446 MHz). The hyperband was used for the transmission of digital television and radio programs in the DVB-C standard. By January 1999, 16 digital radio programs were also broadcast in Germany on 118 MHz using the DSR method. With the modernization of the cable television networks by the cable network operators , the networks were upgraded for frequencies up to 862 MHz in order to be able to offer not only analog and digital programs, but also their own services such as Internet access (return channel capability) using a cable modem or video-on-demand . With the introduction of the LTE mobile radio standard as well as the DAB / DAB + digital radio and the DVB-T / DVB-T2 aerial television , mutual interference can occur. The reason lies in the cable television networks that have been built up and often poorly shielded since the early 1980s.
- (Frequency ranges for Internet access according to Euro-Docsis)
The regulatory authority for the distribution of programs via cable networks lies with the state media authorities of the federal states, i. H. Satellite programs are fed in in accordance with the approvals from the relevant state media authority on the basis of the State Broadcasting Agreement . If the operator of cable networks creates a basic program package , this must in any case ensure the basic public service, i.e. contain ARD ( Das Erste and the respective third program), ZDF and the programs of Deutschlandradio . In addition, no minimum size of the basic package is required. All other channels are assigned according to content allocation criteria, diversity, demand, local reference and media business commitment.
A special feature of the German cable market is the fact that, unlike in other countries, the cable network operators do not pay a fee for retransmitting the programs to the pay-TV broadcasters, but rather the broadcasters pay for feeding their programs into the cable network that they use and have to collect their subscription fees from customers themselves. This regulation is intended to serve competition in the German cable network.
The former television cable network of the Deutsche Bundespost in Germany is now largely operated by Vodafone and the smaller Pÿur .
Network levels of the cable television network
In order to avoid confusion with community antenna systems, network levels were defined for the cable television network in order to be able to make delimitations. The cable network in Germany can be organizationally divided into several network levels:
- Network level 1: between the studio and the television switchboard (television and radio studios and the way to the transmission system , therefore does not belong directly to the cable television network)
- Network level 2: between the television switching point and the BK amplifier point (central facilities such as cable headends)
- Network level 3: between BK repeater and transfer point (the actual broadband distribution network)
- Network level 4: between house transfer point and broadband socket (house distribution)
- Network level 5: terminal area
In other countries, such as Switzerland, this division can be different. In Germany you are usually a customer of a provider at network level 4.
Separation of the cable television network from the communal antenna system
While a community antenna system (GA) in hotels or blocks of flats has up to a few hundred participants, large community antenna systems (GGA) are intended for several hundred subscriber connections and objects that are further apart.
Extended use of the cable television network through broadband services with return channel capability
With the sole analogue and digital cable television offering, the operators no longer see any further market development opportunities in the long term. That is why many cable network operators have expanded their networks to include so-called broadband services using a return channel. This enables the customer to use telephony and internet-based broadband data services through the broadband internet access using a cable modem . (Conversely, nowadays there are also landline providers such as Deutsche Telekom who make their existing telecommunications network suitable for the transmission of television programs in some places and can thus also offer telephone connections, Internet access and television programs at the same time - as a competitor to the previously described possibilities of modern cable connections. Communication in two directions is the basic principle of the network there anyway.)
Cable networks in standardization
The technical performance of broadband cable networks is regulated by the Data Over Cable Service Interface Specification, DOCSIS for short.
In Germany, the DKE Standards Committee K 735 is responsible for developing and updating the standards. These have their origins in VDE 0855 "Regulations for external antennas" from 1925, one of the regulations of the Association of Electrical, Electronic and Information Technologies (VDE) with a long tradition.
With the transfer of the work results to CENELEC at the end of the 1980s, standardization activities were continued at European level. The results are adopted by the IEC as global standards. For some standards, work has now been shifted to the IEC. Through directives of the European Union ( low voltage directive , EMC directive , directive 1999/5 / EG on radio systems and telecommunications terminal equipment), some of the standards are given legal character for all European member states.
The standards for cable networks are summarized in the series DIN EN 50083 and 60728 (VDE 0855) "Cable networks for television signals, audio signals and interactive services ". The following list is based on the classification in the VDE regulations (system standards):
- VDE 0855-1: "Safety requirements"
- VDE 0855-3: "Active broadband devices for coaxial cable networks"
- VDE 0855-4: "Passive broadband devices for coaxial cable networks"
- VDE 0855-5: "Devices for headends"
- VDE 0855-6: "Optical devices"
- VDE 0855-7: "System requirements"
- VDE 0855-8: "Electromagnetic compatibility of cable networks"
- VDE 0855-9: "Interfaces for CATV / SMATV headends and comparable professional devices for DVB / MPEG-2 transport streams"
- VDE 0855-10: "Return channel system requirements"
- VDE 0855-200: "Electromagnetic compatibility of devices"
- VDE 0855-300: "Transmit / receive antenna systems for transmitter output powers up to 1 kW - safety requirements"
- Supplement 1 VDE 0855: "Guide to equipotential bonding in networked systems"
- Technological and economic long-term prospects for telecommunications (PDF; 2 MB)
- Association of providers of telecommunications and value-added services e. V.
- Background report on the technical functioning of a cable network on teltarif.de
- ^ Cable & Satellite Europe Magazine. Jan. 1994
- ↑ Telekom is allowed to keep the network in: Die Welt from March 4, 1997
- ↑ The time 23/1998: The Digital pact between Kirch and Bertelsmann - Europe spektakulärster case
- ^ Golem.de February 2000: Telekom sells cable network in NRW
- ^ Teltarif March 2003: Deutsche Telekom completes sale of remaining cable networks
- ↑ http://www.kabelfernsehen-kabelverbind.de/artikel/wie-funktioniert-ein-kabelnetz