The Data Link Control (DLC) protocol driver provided with Windows NT allows the computer to communicate with other computers running the DLC protocol stack (for example, an IBM mainframe) and other network peripherals (for example, printers such as a Hewlett-Packard HP 4Si that use a network adapter card to connect directly to the network).
Windows NT DLC contains an 802.2 Logical Link Control (LLC) Finite State Machine, which is used when transmitting and receiving type 2 connection-oriented frames. DLC can also transmit and receive type 1 connectionless frames, such as Unnumbered Information (UI) frames. Type 1 and 2 frames can be transmitted and received simultaneously.
Windows NT DLC works with either token ring or Ethernet MAC drivers and can transmit and receive Digital.Intel.Xerox (DIX) format frames when bound to an Ethernet MAC.
The DLC interface can be accessed from 32-bit Windows NT-based programs and from 16-bit MS-DOS–based and 16-bit Windows-based programs. The 32-bit interface conforms largely to the CCB2 interface, the segmented 16-bit pointers being replaced with flat 32-bit pointers. The 16-bit interface conforms to the CCB1 interface.
Note For definitions of the CCB interfaces, see the IBM Local Area Network Technical Reference.