Abstract: A technique for inclusion within, e.g., ISDN DTE, and use in conjunction with an ISDN terminal adapter (as DCE) for automatically providing ISDN switch type detection and SPID configuration. Specifically, switch type detection occurs by analyzing D-channel ISDN initialization messages received from the local ISDN switch as well as, subsequently, where appropriate, responding D-channel ISDN messages, received from the switch to specific ISDN messages sent by the adapter. If the switch type is one that requires a SPID, a SPID is formed using a predefined generic NI-1 format, for each B-channel through which communication is being established, and sent to the switch, using an NI-1 terminal initialization request, to invoke initialization.