Copper cables

Cabelte starts the production of copper telecommunication cables since the early 1970’. The first copper cables were made of PVC insulated conductors twisted in pairs.

The rise of the new generation of cables with better characteristics for transmission, takes place in the 80s with the use of solid and cellular polyethylene as insulation material.

Today, the use of copper telecommunication cables embraces other applications, as a result of the progress revealed on transmission systems. In the’ 90s, a new generation of cables for customer premisses appears, adapted,not only for voice, but also for image and data transmission, with optimized performance capable of supporting high transmission rates.

In general, the basic unit of a copper telecommunication cable is made of two insulated conductors, twisted together, with a constant lay length in order to create a balanced circuit. One may also group 4 conductors, twisted together, forming a quad which may contain, within itself, two or three transmission circuits.

With the frequency increase and use of multichannel transmission, it became necessary to optimise and improve cables characteristics in order to minimize interferences between pairs, usually called “cross-talk”, distinguishable as pieces of speech or signalling tones leaking from other people’s connections. Cabelte was continually investing and optimizing its production processes, in order to achieve the manufacturing of cables, complying with progressively demanding parameters, prescribed by communications upgrade and applicable standards.

The fulfilment of a certain communication specification and characteristics applied, such as attenuation levels and maximum crosstalk (near end crosstalk and far end crosstalk), among others, immediately starts at the project stage, by determining pair capacity and resistance, thickness of insulated wire, insulation material to be used, screens sizing and application methods, lay-length of each pair or quad and their assembly.

The production process has a decisive role in obtaining the desired characteristics, very important is the tight control of all parameters, both at extrusion (application of insulation layer) reducing all dimensional variability, and, at stranding, by tightly controlling tensions and constancy of pitch.

Cables can be made by only one elementary circuit (pair) or more, there are cables with several hundred pairs, the composition can reach 2400 pairs. These high-capacity cables require a complex systems of identification, as each pair must be clearly identified from the others. This is achieved through a complex system of identification, carried out by using different colours for insulation, sometimes using rings marking and also by a set of coloured tapes applied on pairs groups.

The tightness of telecommunication cables for outdoor use is properly secured, since the entry of water in a cable can lead to small failures in insulation deteriorating transmission quality. Thus, in some designs, a jelly is applied to prevent water progression inside the cable. Transversal tightness reinforcement is usually achieved by the longitudinal application of an aluminium polymer coated tape thermo-welded to the sheath. This tape also functions as shielding.

Cabelte offers a very wide range of copper telecommunication cables, meeting the specifications of various telecomunication operators both national and international, and private customers. The current range points up 5 major groups:

- Cables for local area networks connecting subscribers to their centrals, establishing connections between centrals and private telephone networks. Within this range, one can find solutions adapted to indoor and outdoor, for underground or aerial installations;
- Quad Cables for regional networks, typically used for connections between centrals, but also for private telephone centrals;
- Cables for transmission of digital signals in PCM circuits up to 30 channels (2Mbit/s) in 2 directions;
- PVC cables for subscriber network, inside buildings, and polyethylene cables for use in the distribution network access, establishing the connection to the subscriber, with transmission characteristics of category 3 (16Mhz);
- Cables for customer premisses suitable for 100MHz or higher transmission frequencies.