40GBASE-ER4

40GBASE-ER4 is a standard for high-speed data transmission over fiber optic cables, capable of transmitting 40 gigabits of data per second. It uses four wavelengths of light to send data simultaneously over a single fiber, increasing capacity and efficiency. This technology is commonly used in data centers and enterprise networks to connect servers and switches over longer distances, typically up to 40 kilometers—making it essential for high-performance, long-range network communications.