Abstract: Apparatus for an improved ISDN terminal adapter (5) and accompanying methods for use therein. The adapter provides automatic ISDN switch detection, automatic SPID configuration, baud rate unblocking and automatic data compression. Specifically, the adapter automatically provides B-channel data compression in the event the DTE is unwilling or unable to do so. Here, the adapter monitors negotiation, over an ISDN line, of a compression control protocol (CCP) between the DTE and its PPP peer (380). If the negotiations reveal that the DTE will not undertake compression, then the adapter will then automatically negotiate the protocol and thereafter, for the duration of a call, perform compression and decompression in lieu of the DTE.