Asyncmac.sys supports software compression over RAS on NT and NTAS 3.1. RASmac.386 supports software compression over RAS on WFW 3.11. Both types of compression are compatible with each other. Back up your current files with the same name or rename them and copy the corresponding one in its place and restart your computer. The Asyncmac.sys belongs in the %NTRoot%\system32\drivers DIR. The WFW 3.11 RASMAC.386 belongs in the %Windowsroot%\system DIR. Microsoft has not tested the Asyncmac.sys file provided with this file on systems with Service Pack 2b or Service Pack 3, and therefore makes no guarantees as to its performance, however, we have no reason to believe that the user will encounter problems.