Copper vs. Fiber Optic Cabling: Encoding, Security & Connectors
Copper and Fiber Optic Cabling: Encoding, Security & Connectors
Encoding Bits as Voltages
There are two primary ways bits are encoded as voltages, each with distinct characteristics:
- Non-Return to Zero (NRZ) Coding: In NRZ, a ‘0’ bit is represented by one voltage level, while a ‘1’ bit is represented by a different voltage level. The voltage remains constant during the entire bit time.
- Manchester Encoding: Manchester encoding uses transitions in voltage to represent bits. For example, a ‘0’ is indicated by a transition from high to low in the middle of the bit time, and a ‘1’ is indicated by a transition from low to high in the middle of the bit time.
Encoding Bits as Symbols
Bits can also be encoded as symbols before transmission. The physical layer uses coded symbols, known as code groups, to represent control information or data links. A code group is a sequence of bits that represents a specific pattern of data. For example, the code bits ‘10101’ might represent the data bits ‘0011’.
While code groups introduce overhead in the form of extra bits, they enhance the strength of the communication link, especially for high-speed data transmission. Symbols improve error detection and timing synchronization between transmitting and receiving devices.
Advantages of using symbols:
- Reduction of bit-level errors
- Mitigation of limitations in effective energy transmitted
- Improved distinction between data and control bits
- Enhanced error detection
Security Issues with Copper Wiring
When using copper wiring, several security issues should be considered:
Electrical Hazards
Copper wires can conduct electricity in unintended ways, potentially exposing personnel and equipment to electrical hazards. A defective network device can drive current to the chassis of another device. Network cabling can also introduce unwanted voltage levels when connecting devices with different ground potentials. Copper wiring can also conduct voltages that cause electric shocks to network devices.
These currents and voltages can damage network devices and computers or cause injury to personnel.
Fire Hazards
The coating and insulation of copper wires can be flammable and release toxic fumes when heated or burned. Organizations and municipal authorities often have security standards for hardware and wiring installations.
Fiber Optic Cable vs. Copper Wiring
Fiber optic cable is preferred over copper wiring in certain situations. Because the glass fibers used in fiber optic media are non-conductive, they are immune to electromagnetic interference and do not conduct electrical current. Fiber optic cables can be used over much greater distances than copper cables without signal regeneration, as they are thin and have relatively low signal loss.
Types of Copper and Fiber Connectors
Copper Connectors:
- RJ-45
- RJ-11
Fiber Connectors:
- Punta Straight (ST)
- Subscriber Connector (SC)
- Lucent Connector (LC)