Abstract: The present disclosure relates to data transmission methods, systems, and apparatuses. In one example method, a first device sends first information of a first data block to a second device. The second device searches, based on the first information, a first index for a second data block similar to the first data block, and sends second information of the second data block to the first device. The first device locally obtains, based on the second information, a reference block that is the same as the second data block, compresses a difference part of the first data block relative to the reference block to obtain first compressed information, and sends the first compressed information to the second device. The second device obtains the first data block based on the first compressed information and the second data block.

Abstract: The present invention relates to a building management system based on identifiable marks that are arranged on terminal devices of a building and have a one-to-one correspondence with the terminal devices' own codes, the building management system comprising a user terminal, and the user terminal storing a database comprising codes of the terminal devices and comprising a scanning device for identifying and determining the identifiable marks, wherein an actual or relative location of the user terminal in the building can be determined by identifying and determining at least two identifiable marks. Moreover, the present invention further relates to an implementation method for the building management system based on identifiable marks. The building management system based on identifiable marks according to the present invention favors building management and the design, installation, debugging, management, and maintenance of terminal devices.