Data Link Control (DLC) was originally developed for IBM mainframe communications. The protocol was not designed to be a primary protocol for network use between personal computers. The other use of DLC is to print to Hewlett-Packard printers connected directly to networks. Network-attached printers use the DLC protocol because the received frames are easy to disassemble and because DLC functionality can easily be coded into read-only memory (ROM). DLC's usefulness is limited because it doesn't directly interface with the Transport Driver Interface layer. DLC needs to be installed only on those network machines that perform these two tasks, such as a print server sending data to a network Hewlett Packard printer. Clients sending print jobs to a network printer do not need the DLC protocol. Only the print server communicating directly with the printer needs the DLC protocol installed.
For more information about DLC, see "Data Link Control" in the Windows 2000 Internetworking Guide .