The loss of signal strength with long distances when signals travel along cabling. Attenuation values for actual cables are measured in units of decibels (dB) - a standard measurement value used in communication for expressing the ratio of two values of voltage, power, or some other signal-related quantity.

For example, a drop of 3 dB corresponds to a decrease in signal strength of 50 percent or 2:1, while a drop of 6 dB corresponds to a decrease of 75 percent or 4:1. Attenuation values for cabling media are expressed in units of decibels per 1000 feet, which express the amount of attenuation in decibels for a standard 1000-foot length of cabling composed of that media.

Copper cabling has much greater attenuation than fiber-optic cabling; therefore, copper is suitable only for relatively short cable runs. Typical attenuation values for copper category 5 cabling vary with frequency and are shown in the table that follows. Attenuation for lower-grade cable is slightly higher.

Signal Frequency | Attenuation |

4 MHz | 13 dB/1000 feet |

10 MHz | 20 dB/1000 feet |

20 MHz | 28 dB/1000 feet |

100 MHz | 67 dB/1000 feet |

Attenuation is caused by signal absorption, connector loss, and coupling loss. To minimize attenuation, use high-grade cabling such as enhanced category 5 cabling. Also try to minimize the number of connector devices or couplers, ensuring that these are high-grade components as well. When a signal attenuates a large amount, the receiving device might not be able to detect it or might misinterpret it, therefore causing errors.