low layer compatibility (ISDN) (LLC)

Low Layer Compatibility(LLC) is an information element for compatibility information between two ISDN or GSM terminals.

This information element ensures that no transmission can take place between incompatible terminals, for example between a telephone and a fax machine. The LLC element can contain the parameters and protocols used in the lower three layers of the user channel and transmits them in ISDN fully transparently to the called terminal.