As a landline , the ensemble of all public wireline is telephone networks called. In this context, wired is primarily understood to mean the last mile , i.e. the connection to the end customer. Public networks, as part of the fixed network, can be state or privately owned, but are only available to the general public either regionally (e.g. NetCologne ) or nationwide (e.g. the Deutsche Telekom telephone network ) and are subject to German-speaking countries the requirements of the relevant state telecommunications laws.
The word "fixed network" only found its way into everyday language around the turn of the millennium, when more and more people were buying cell phones at that time. Before that, the fixed network was simply called the "telephone network".
The fixed network is divided into the core network and the access network.
The core network connects the individual switching nodes with one another. The physical basis is formed by twisted copper wires (double or quadruple), coaxial cables , directional radio and fiber optics . Several channels are combined into a large one by means of multiplexing . With the “almost synchronous transmission” of PDH technology, transmission rates of up to 564.992 Mbit / s are possible. The more modern SDH technology achieves data rates in the Gbit / s range. The PDH technology is therefore being replaced by the SDH technology and is only used in the access network for new installations.
The access network connects the end users with the switching nodes (see last mile ).
The beginning of the communication networks were manual exchanges, which were set up in a star shape and connected to one another by the "Fraulein vom Amt" . From the beginning of the 20th century, this manual switching was gradually replaced by electromechanical switching elements, but the hierarchical structure was retained. At that time, seven central offices in Germany formed the top level of the network, each with its own code number. This level was fine-tuned in three further steps. A telephone number was built up through this structure - < long-distance traffic number (0) > - < central office > - < main office > - < node office > - < local office > and the subscriber number . This resulted in up to five-digit dialing codes that are still used today in the German landline network. However, as the volume of calls between two offices increased, cross-connections had to be installed, so that the strict hierarchy was increasingly dissolved. The web became an incomplete mesh . In the meantime, the electromechanical switching elements have been completely replaced by highly integrated circuits, the so-called switching matrices, and their control. Today the network is divided into two levels:
- Location level VE: O (exchange unit location) and
- Remote level VE: F (remote switching unit).
There is also an international placement service (VE: A).
|year||landline||Cellular (without roaming traffic)||OTT provider ( Skype , FaceTime, etc.)|
In Germany there are 38.52 million landline connections (as of 2017), over which calls are made 120 billion minutes a year (as of 2017). There are also 24.3 million DSL broadband connections, 7.4 million HFC broadband connections, 775,000 FTTB or FTTH broadband connections, and 27,000 satellite broadband connections (as of 2017) with an average data volume of 74 GB per month (as of 2017).
The CIA reports that in 2003 there were around 844 million fixed-line routes worldwide.
The People's Republic of China has the largest part with 263 million, in second place the United States with 181.6 million fixed network routes. By comparison, there are 158.7 million cell phones in the United States .
All over the world it is expected that in a few years the number of mobile radio subscribers will exceed the number of subscriber lines . According to an estimate by the Federal Network Agency , every German called an average of 60 hours in 2011, 39 hours of which were via landline. The number of call minutes from mobile communications rose by 10 percent from 2009 to 2010. In 2011, the number of call minutes on the fixed network fell by 2 percent to 191 billion.
Differentiation from mobile communications
A distinction is made between the fixed network and the mobile network , consisting of the PLMN and the access network, the connection to the end customer, which takes place wirelessly via the so-called air interface .
The distinction between landline and radio is mainly made for the last mile , where telephone calls are routed to a localized subscriber line. Here is the infrastructure mostly as earth cable with copper - twisted pair run. Fiber optic cables have also been used for a number of years . In addition to analog telephony, other services, including ISDN and DSL , can also be enabled via the cables of the subscriber lines . However, DSL technology is limited to copper cables.
Only in the military sector is the core network regularly set up with mobile connection points.
Details on the line types in the fixed network
- possible frequencies: 0 Hz – 100 kHz
- Repeater distance : 2–20 km
- Bandwidth : <10 kHz
- Bit error rate :?
- Examples: Aboveground telephone line, out of date, mainly used in Germany in the internal telephone network
- possible frequencies: 0 Hz – 750 MHz
- Repeater distance : approx. 1.2 km
- Bandwidth : 100-600 kHz
- Bit error rate : approx. 10 −5
- Details on ADSL via copper pairs are regulated in guideline G.992.1 .
- Examples: telephone network ( subscriber connection area ), Ethernet
- possible frequencies: up to 5 GHz
- Repeater distance: 1–10 km
- Bandwidth: 900 MHz
- Bit error rate: approx. 10 −7
- Examples: telephone network (network internal), ethernet , cable television , antenna cable
Carrier Frequency System (PLC)
- possible frequencies: up to 30 MHz (over long distances up to 500 kHz)
- Repeater distance: up to 200 km (depending on the system)
- Bandwidth: up to 20 MHz, for long distances <10 kHz
- Bit error rate:?
- Examples: Wire radio, message transmission on high-voltage lines (carrier frequencies around 1 kHz and between 30 kHz and 500 kHz), PLC connection for PC
PLC systems are an intermediate form of wired and wireless communication, since signals transmitted with PLC systems can also be received in the vicinity of the lines with radio receivers for the corresponding frequencies. This was previously used in Norway with the so-called line transmitters . These were radio transmitters in the long wave range that used power lines for transmission. PLC systems should only be used if the choice of transmission frequency ensures that no radio services in the long and short wave range are disturbed.
PLC is also the name of a process for networking computers or connecting them to the Internet (called in-house communication when operating within a house). The operation causes disturbances in the shortwave range via the domestic or public power supply lines. Weak shortwave transmitters are overlaid with a strong noise or staccato noise, which can also be heard in neighboring houses or apartments. In this case, the Federal Network Authority can prohibit the operation of these devices.
- used wavelengths : 850 nm, 1300 nm, 1310 nm, 1550 nm or 1625 nm
- Repeater distance: 10–100 km
- Data rate (per channel, i.e. wavelength): up to 40 Gbit / s, in the laboratory 160 Gbit / s
- Examples: telephone network ( subscriber connection area ), FDDI
- Telephone connection
- Telephone cord
- Digital Subscriber Line # broadband providers_and_market shares
- Hauser BJ, Textbook of Communication Technology - Introduction to Communication and Network Technology for Studies and Vocational Training (2010), pages 232f., ISBN 978-3-942693-24-0
- Hauser BJ, Textbook of Communication Technology - Introduction to Communication and Network Technology for Studies and Vocational Training (2010), p. 230ff., ISBN 978-3-942693-24-0
- 17. TK Market Study Germany 2015. (PDF) (No longer available online.) VATM and Dialog Consult, October 21, 2015, p. 23 , archived from the original on March 4, 2016 ; accessed on November 11, 2015 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- Federal Network Agency Telecommunications Activity Report 2016/2017
- BITKOM : 1805: Voice telephony moves from the fixed network to the mobile network ( memento from June 15, 2012 in the Internet Archive ), press release, February 19, 2012, accessed on March 3, 2012