A retimer is provided. The retimer includes: a data channel circuit, configured to implement, under a function of a current phase locked loop, equalization processing-based transparent transmission of a signal between a first communications device and a second communications device; and the link adjustment circuit, configured to: when determining, based on link status information of the data channel circuit, that a rate of a link needs to be changed, configure an operating parameter of a target phase locked loop as an operating parameter corresponding to a changed rate; and switch the currently used phase locked loop to the target phase locked loop when detecting that the link enters a rate-changing state, where the data channel circuit is further configured to implement, under a function of the target phase locked loop, the transparent transmission of a signal between the first communications device and the second communications device.