The AB end of fiber optic transceivers is usually used in pairs, with A end used for transmission and B end used for reception. People can divide fiber optic transceivers into single fiber transceivers and dual fiber transceivers based on the number of cores connected, but there are more people using single fiber transceivers on the market. The single fiber transceiver has two ends, A and B, with different wavelengths. The wavelength of the transmitting end is shorter than that of the receiving end, while the dual fiber transceiver does not distinguish between the AB end because the wavelengths at both ends are the same, only the TX (transmitting) end and the RX (receiving) end when connected. Single fiber, as the name suggests, is a single fiber, also known as a single core transceiver by some professionals. It refers to the transmission and reception of signals at both ends on a single fiber, because the optical module used inside a single-mode single fiber transceiver has two emission wavelengths, while dual fibers are connected by crossing two fibers, and the internal optical film block has only one wavelength.
