Know Your Cables and Transceivers.

Common Terminologies

  • Modal Bandwidth – Maximal signaling rate for a given distance or the maximal distance for a given signal. Calculated as the product of bandwidth and distance (
  • Patch Panels – Hardware units with multiple ports, each connecting to a different location, allowing for the organization of a group of cables. They are passive devices.
  • Form Factor – In the context of transceivers it refers to the size, shape and electrical interface of the device.
    • Small Form-Factor Pluggable (SFP): They are compact optical or copper modules used in networking equipment to transmit and receive data over single channel of fiber optic or copper cables.
    • Quad Small Form-Factor Pluggable (QSFP): Compact optical transceiver module that supports four independent channels of data transmission over fiber optic cables.
    • Quad Small Form-Factor Pluggable Double Density (QSFP-DD): Supports eight channels of data transmission.
  • Attenuation – Reduction in signal strength or intensity as it travels through a medium such as an optical fiber or transmission line.
  • Channel – Combination of independent data paths used to receive and transmit data.
  • Baud Rate – Measure of the rate at which data is transmitted over a communication channel and typically expressed in symbols per second (baud).

Interconnect Options

There are three major interconnect types.

  • Direct Attach Copper Cable (DAC): Has two electrical interfaces at the end of a copper cable.
  • Active Optical Cable (AOC): Has two electrical interfaces at the end of an optical cable made of optical fiber.
  • Transceiver Module+Connector+Transmission Cable(Optical /Copper)


Based on transmission medium, cables can be categorized into two broad categories; Copper and Fiber Optic.

1. Copper UTP/STP Cable

2. Optic fiber Cable

2.1 Types of Optic Fiber Cable

Types of Multi Mode Fiber



Consider below example


10G – Describes the maximum speed supported by the module. Other variants include 1G/10G/25G/50G/100G/40G/400G

SFP – Describes the physical form factor. Other variants include SFP/QSFP/QSFP-DD

+ – Describes the version of the form factor subjected to maximum speed. Other variants include +/28/56

LC – Describes the type of connector supported. Other variants include LC/MPO12/MPO16/SN

SR – Describes the achievable distance. Other variants include SR/LR/ER/DR/FR

Understanding Short Reach (SR) standards

Understanding Long Reach (LR) standards

Understanding Extended Reach (ER) standards

Understanding Bi-Directional (BiDi) standards

Other Optical Standards