Support of Existing Data Interfaces by the ISDN

During the past decade, the opportunity has arisen to economically combine data and voice services onto a single system, the integrated services digital network (ISDN). Studies in CCITT have led to the production of a set of Recommendations covering aspects of the ISDN, including the customer terminal interface. Inevitably, there are significant differences between the customer terminal interfaces recommended for dedicated data networks and that proposed for the ISDN. To ensure a smooth transition towards the introduction of ISDN based services, the CCITT have published recommendations describing how existing terminal interface designs may be connected to an ISDN. These recommendations are the subject of this paper.