Types of DSL
1. IDSL (ISDN Digital Subscriber Line)
The technology is based on technology ISDN BRI (Basic Rate Interface). IDSL offers services such as BRI with the send speed (uplink) and receive (downlink) the same of 144 kbps, but with the cheaper devices. IDSL is only offering data communications services not for voice communications on the same line.
2. SDSL (Symmetric Digital Subscriber Line)
This technology uses 784 kbps data speeds, good for send (uplink) or received (downlink). As well as IDSL, SDSL offer only data communication only. SDSL is a suitable solution for business circles to be used the US communication between branches or the relationship web sites to the internet. SDSL is suitable for high speed internet access for housing because it gives the speed or bandwidth of up to 2.3 Mbps and is symmetrical, with a maximum distance to 2.4 km. ideal for Remote LAN access (remote LAN), VOD (Video On Demand), residential converencing and video others.
3. ADSL (Asymetric Digital Subscriber Line)
These technologies have different data rates to send (uplink) and receive (downlink). ADSL technology suitable for accessing the internet and became the choice of the user. For up to 8 Mbps uplink to downlink could reach 1 Mbps maximum cable distance to Target by 5.5 km. this technology is especially more private customers receive data instead of sending data, for instance was to access the internet.
The advantages of ADSL compared to others is the highest velocity with an adequate distance and can support voice communication services. Both data and voice communications services are provided through two separate canals, but keep the same one cable. While the other DSL technology uses two separate cables for both services can give you such communications.
Due to various advantages of ADSL technology that is owned by this then this technology is growing very fast. Data transmission via ADSL is carried out by several stages. The modem modulates and encode digital data (encode) from the PC and then combined with the phone's signal to send to the Office phone. In the Office the phone the phone signal is separated from the digital signal for later encoded. Through a network of data communication signal is sent to the other party, such as an ISP or other offices. the data network used is depending on the service provider ASDL, could frame relay or ATM (Asynchronous Transfer Mode).
While the digital signal from YOUR ISP or company network to another is modulated and encoded into signals ASDL in Office phone. Then combine with the modem phone signal before sent to customers, the separator (splitter) separating signals from digital signals. The digital signal is modulated and decode and then sent to the PC. The phone signal is combined with the signal in one cable ASDL stays in power by give the phone company. Although ADSL line not working or no PC turned on phone line can still function us usual. There are two different modulation techniques are applied on ADSL.
The first modulation technique is to apply the techniques of modulation of CAP (Carierless Amplitude and Phase). The CAP combines upstream and downstream data signal, then separating them on the receiver and modem with echo cancellation techniques. The other modulation techniques are DMT (Discrete Multitone), which separates signals upstream of downstream signal with the Ribbon carrier (carrier band). In the future the ADSL products will use the technique of modulation DMT.
4. the VDSL (Very high-bit-rate Digital Subscriber Line)
VDSL technology are asymmetric. The range of operations is limited to 1.000 to 4.500 feet (304 metres-1.37 Km), but he can handle the bandwidth the average 13Mbps to 52 Mbps to 1.5 Mbps downstream and up to 2.3 Mbps upstream for him through a pair of copper wire winding.
The remaining bandwidth allows telecommunications companies provide program service HDTV (high-definition television) and VDSL technologies. This technology can also transmit data at speeds of 1.6 Mbps and receive data at speeds of 25 Mbps with maximum distance up to 900 meters. Because of this the high technology it requires fiber-optic cables that his ability is higher than the existing copper cable wear.
5. HDSL (High data rate Digital Subscriber Line)
HDSL is suitable for Office buildings or office complexes, because it gives the speed or data width to 10 Mbps and can be assigned to all end users. The infrastructure required for this connection HDSL can use PBX line owned the building, without having to menginvestasi the construction of computer networks.
The maximum distance is long enough to reach 1 km. HDSL wearing two pairs of twisted cable that will carry data at speeds of 1, 544Mbps upstream (from the customer to the network) and downstream (from the network to the Subscriber). Moreover technologies also HDSL also use three pairs of twisted cable with speed 2, 048Mbps with data rate up to 12 feet.
6. RDSL (Rate Adaptive Digital Subscriber Line)
RDSL is one of DSL technology, where this technology can work on different data rate depends on the cable length and the distance is.
