Optical transceivers are divided into three categories: PDH, SPDH, SDH. PDH (Plesiochronous Digital Hierarchy) optical transceiver is a 120-channel photoelectric integrated transmission device composed of ultra-large-scale integrated circuits, generally a paired application, also called point-to-point application, the capacity is generally 4E1, 8E1, 16E1; Applicable to small-capacity switch networking, user loop network, mobile communication (base station), private network, DDN network, etc. Its main features are: the use of ultra-large-scale integrated chips, with low power consumption and high reliability. Provides the remote loopback test function of E1 for easy maintenance. The 120 provides four E1 channels; it has a complete alarm function to display local and remote alarms. The alarm information (including the power failure alarm) can be reported to the peer through the network management channel. The transceiver is integrated and integrated, and the working performance is stable and reliable. The design of the whole board is small and easy to use. The SDH (Synchronous Digital Hierarchy) optical transceiver has a large capacity, generally 16E1 to 4032E1. SPDH (Synchronous Plesiochronous Digital Hierarchy) optical transceiver, between PDH and SDH. SPDH is a PDH transmission system with SDH (Synchronous Digital Series) features (based on the principle of code rate adjustment based on PDH, and at the same time adopts some networking technologies in SDH). The optical transceiver is classified into a video optical transceiver, an audio optical transceiver, a data optical transceiver, an Ethernet optical transceiver, a switching optical transceiver, and a telephone optical transceiver. In terms of monitoring terminology, it is a video optical transceiver that transmits video and other data, audio, switching, and Ethernet telephone signals. The essence of this is: photoelectric conversion transmission equipment; placed at both ends of the cable, One receipt and one shot, as the name suggests, the optical transceiver; in a broad sense, the photoelectric conversion equipment based on the optical network for transmitting signals can be called optical transceiver. This classifies compressed optical transceivers for transmitting signals on telecommunications (also with compressed video) and uncompressed video optical transceivers for the surveillance and broadcast television industries. Graphite Plate for Vacuum Pumps,Carbon Vanes for Vacuum Pump,Vacuum Pump Carbon Sheet Dongguan Beqile Mechanical&Electrical Equipment CO.,LTD , https://www.betemvacuum.com