Advertisment

Electrifying Communications

author-image
VoicenData Bureau
New Update

A

wise man once said, progress is the path from the primitive, via the complicated

to the simple.

Thanks to Power-line CommunicationsÂ

(PLC), telephoning via the electricity supply network from any power

supply socket to any telephone in the world is possible now.



Advertisment

 “I

need to send some urgent e-mails. Where can I connect my PC to the network?”

Shahid Ali asked the receptionist shortly after his arrival at his company’s

freshly opened branch office. “I know that when the building was being

renovated it was planned to have a communication socket in every room, but I

cannot find one!” The receptionist’s radiant smile quickly soothed the new

colleague, but her answer almost knocked him for six. “Every power socket in

this building is a communications connection. And you not only have Internet

access, you can telephone as well.”



Difficulties Overcome

This scenario could occur in every office

building or household in the not too distant future. Since what was once thought

to be impossible has become a reality: Telephoning via the electricity supply

network from any power supply socket to any telephone in the world. For a long

time even the experts doubted this development. The objections against a

universal network for electricity supply and communications were overwhelming.

The electricity supply network is considered to be an extremely demanding

transmission channel. Since the signal, which is fed into the network suffers

attenuation on the long path from the transmitter to the receiver. The greater

the distance, the greater the attenuation. Over and above this the

electromagnetic compatibility of PLC is regarded as a real challenge.

Interference must be avoided. Thus certain frequency bands are disallowed for

wire bound transmission procedures such as PLC, depending on national

regulations.



Advertisment

In principle, it is

possible today for every electricity socket to be turned into an interface for a

PC printer, telephone or other communications devices. And solutions are

available today that offer communication over the electricity supply network.

Vendors claim that the transmission over the electricity supply network using

PLC is so good that for the first time voice traffic and high speed data can be

transmitted right from the transformer station to every socket in the building.



The success potential

of the PLC approach does not, however, lie just in the technology but also in

the new services which can be implemented using it. All devices that are powered

from the mains supply are connected to the same network. Hence diverse new

service and applications come to mind which will combine communications and IT

devices such as the telephone and the PC with traditional electrical devices.

Examples range from facility management, credit card verification, the control

of heating, air conditioning or ventilation systems, through to electronic

newspapers and tele-conferencing. The broadband PLC system with which Ali’s

company will soon be equipped, permits access to the network from every room in

the building without the need to lay new cables.



The system functions

as follows: In the electricity supply company’s transformer station, a PLC

modem modulates the high frequency signal of the telecommunications backbone

network onto the low-voltage local electricity supply network over which it is

carried into the building. According to vendors data rates of more than 1 Mbit/s

have already been achieved. This is 20 times the speed of ISDN, which is 64 Kbit/s.

It is important to note that the PLC solution not only covers the path from the

transformer station to the building but can also connect the mains supply

circuits within the building. Every power socket in the building is thus

connected to the communications network. This brings tremendous advantages, for

example, for a company that needs to install a local area network in an old

building. After all, the in-house PLC local area network for networking

computers and peripheral equipment can easily be based on the existing mains

cabling.



Advertisment

The electricity supply

cables permit solutions with which transmission rates of up to 10 Mbit/s can be

achieved. Every PLC modem provides two transparent interfaces for TCP/IP so that

the system can easily be integrated into existing computer networks.



It is important to

ensure that the further development of PLC does nor result in proprietary

solutions. Rather, an open power-line platform must be built up with interfaces,

which are strictly defined. The services that are to be offered over the

low-voltage power supply network are then “mounted” on this open platform.

Solutions should also take investment costs into account. The interfaces of the

PLC are oriented to existing technologies and standards. PLC customers will get

an “Always On” service. It is for this reason that packet-oriented solutions

as used in the Internet, for example, are used. Equally, the interfaces must

also be the customary ones (Ethernet, USB, etc.). It thus makes sense for PLC

solutions to be created through close cooperation between electricity supply

companies, telecommunications suppliers and service providers. Then in future

there will be: One network for everything.



Advertisment