The user message length of the European standard transponder used in our country is 1023bit or 341bit. Based on inquiries related to public information. The transponder is a transmission device that can send message information to the on-board subsystem. It can be simply understood as a data memory and wireless transmitter. The transponder is installed in the center of the track. When the train passes over the transponder, it receives radiation from the antenna unit. Working with power, the message stored in the transponder or the message of the trackside electronic unit (LEU) (active transponder only) is sent to the BTM, and the BTM sends the received data information to the on-board control core. Receive radio frequency energy function: After the transponder establishes the working power supply for uplink transmission, it should send uplink signals to the antenna unit through electromagnetic induction. The data transmitted in the uplink originates from the non-volatile memory in the transponder or from the serial data stream of interface C. Message length: 1023bit or 341bit, maximum external size: 480mm×260mm×42mm (length×width×height). Weight: Active transponder is about 7 kg (including tail cable), passive transponder is about 4.4 kg.