If you create a USS file by providing a control card of USSPATH=(uss path name) you can also use a control card of USSCOMP=Y to instruct Acquire to write data to the USS directory of your choice and then compress it to save space and make for quicker transmission to the Control Center system. Compressed USS files are generally around 10% of their original size. The file name is changed from _asz* to _ezz* to reflect the fact that the data is now compressed EBCDIC characters. Control Center picks up uncompressed data in ASCII mode, but for compressed files it will use a binary mode connection.
If you intend to copy compressed files to Control Center yourself, you should make sure that a binary mode transfer is performed or else data will not be processed correctly.