A half Length Zorro II ISDN Card (single channel, 64Kbit) which is fully CD96 (Q931) compliant. The ISDN card emulates the Hayes Command Set as used by Hayes compatible modems so virtually any software designed for use by modems can be used with the ISDN Surfer. The card also supports additional extentions to the command set, for example Caller ID. Although the ISDN card is single channel, it can still use both ISDN channels independantly of each other. There were plans to ship an ISDN phone module for connection to the card, but it seems likely that it was never produced. The card also contains a clock port header for attaching additional expansions. The driver is CAPO 2.0 compliant which means porting ISDN software from other platforms should be easier.