Digital Subscriber Line (DSL) & Other Broadband Technologies: A Detailed Look
Digital Subscriber Line (DSL) and Other Broadband Technologies
1. Loop Telephone Modem (DSL)
The primary advantage of Digital Subscriber Line (DSL) is that the necessary infrastructure is already installed. However, the available speeds are relatively low, which restricts the set of accessible services and imposes limitations on the subscriber.
2. Integrated Services Digital Network (ISDN)
Integrated Services Digital Network (ISDN) necessitates restructuring in terms of access to housing. Its use is justified for settings that offer local area networks in the home. The advantage is the versatility of services based on basic or primary access contracted. Speeds can reach up to thirty 64 Kbps channels, providing a treatment protocol and access.
3. Asynchronous Digital Subscriber Line (ADSL)
Asynchronous Digital Subscriber Line (ADSL) is another variation of DSL technology.
4. Cable Television (CATV) Networks
Cable television (CATV) networks also offer the possibility of using some of their capacity to provide access to telematic services. The achievable bandwidth is high but requires the introduction of a new access infrastructure. In areas such as small towns and rural areas, the deployment of this infrastructure may not be profitable, potentially leaving these areas without access.
5. Local Multipoint Distribution Service (LMDS) Terrestrial Radio Networks
The advantage of Local Multipoint Distribution Service (LMDS) radio networks is that the deployment of service does not require the laying of cables. Therefore, its implementation is quick and not as expensive as CATV networks. However, the service has not yet started, and as in the case of CATV, it will not be available in all areas simultaneously.
6. Satellite Network Access
Satellite access offers great coverage, allowing service provision even in rural or difficult-to-access areas where the deployment of terrestrial infrastructure would be uneconomical. It is easy to disseminate and offers rapid deployment (like any radio technology). This technology provides digital transport for television (digital audio and video), but being digital, it can be used to send not only television but any information. Its advantages are the same as those listed above for satellite communications in general. Additionally, it is a technology designed for the domestic market. Production volumes of the necessary equipment are high, and economies of scale greatly reduce the cost, making it affordable to use this technology to provide data communication to home users. Added to this is the possibility of integrating telematic and TV services available on the digital platform. This access uses technology available today, which can provide inexpensive access, even in areas with low population density where the land access methods listed above are not viable.
7. Power Line Communication (PLC)
Power Line Communication (PLC) is another method for broadband internet access.
8. Wireless Solutions: Wi-Fi and WiMAX
Wireless solutions such as Wi-Fi and WiMAX are also viable options for broadband access.
Definition of Loops
Four loops are defined (numbered 1 to 4), whose positions, as seen from the Data Terminal Equipment (DTE) A, are shown in the accompanying figure. There could be a symmetric set of 4 loops seen from the DTE B.
Loop 1 (Local Digital)
This loop is for a basic operational test of the DTE. Signals transmitted are returned to it for verification purposes. The loop should be established within the Data Circuit-terminating Equipment (DCE), as close to the interface as possible.
Loop 2 (Digital Far)
Loop 2 is designed to allow the station or network to verify the proper operation of the line (or part of the line) and the DCE B. It can only be used with a duplex DCE. For half-duplex DCE, a pseudo-loop 2 can be defined, which will be specified in the Recommendations on the appropriate DCE. The establishment of the loop will be effective when applied in control, regardless of the state of circuit 108, by the DTE to the DCE partner in establishing the loop.
Loop 3 (Local Analog)
Loop 3 is a local loop established in analog mode as close to the line as possible to verify the proper operation of the DCE. It should include the largest number of circuits used in normal operation (particularly, if possible, the signal conversion function), which may, in certain cases, include devices such as signal attenuation.
Loop 4 (Far/D)
This loop connection is only considered in the case of four-wire lines. Loop 4 is intended to maintain the lines based on analog measurements by administrations. Indeed, the tandem connecting pairs of reception and transmission measurements do not allow the connection as a data circuit.