When we talk about RJ45 ("Registered Jack" 45) we refer to a telecommunications network interface for wired connection of voice and data equipment.

This connector has 8 pins or connections and may have a specific category depending on the data transfer speed and bandwidth (category 5e, 6, etc.)

The common application is their use in Ethernet network cables under TIA/EIA-568-B standard that defines the arrangement of pins (pinout), but can also be used for other applications.

- Direct pin diagram:

EIA-568A
Pin No.1: WHITE-GREEN
Pin No.2: GREEN
Pin No.3: WHITE-ORANGE
Pin No.4: BLUE
Pin No.5: WHITE-BLUE
Pin No.6: ORANGE
Pin No.7: WHITE-BROWN
Pin No.8: BROWN

EIA-568B
Pin No.1: WHITE-ORANGE
Pin No.2: ORANGE
Pin No.3: WHITE-GREEN
Pin No.4: BLUE
Pin No.5: WHITE-BLUE
Pin No.6: GREEN
Pin No.7: WHITE-BROWN
Pin No.8: BROWN

- Schematic of crossed pins:

The crossover cable has one end with EIA-568A scheme and the other one with EIA-568B.

SFP transceiver, English small form-factor pluggable transceiver (in Spanish transceiver small form factor pluggable) or, in English, SFP transceiver and abbreviated known as SFP, it is a compact, hot-pluggable transceiver used for data communications applications and telecommunications. They are designed to support SONET, Fibre Channel, Gigabit Ethernet and other common standardsications.

A Gigabit Interface Converter (GBIC, for short) is a module that is available in many forms, depending on the model and manufacturer of the brand. Each has the same function which is to increase the speed of data transfer through a network. Companies that need to transfer large amounts of data quickly, sometimes using a GBIC module for greater control and profitability. A GBIC moduleIt allows users to reconfigure fiber links, set costs of adapting the receptor and link distances network topologies and requirements established. Used in an optical fiber or Ethernet system, the GBIC modules can update, change or connect without turning off the computer. This flexibility eliminates the need to replace the entire network system together.