COMMON-ISDN-API can be evaluated as an invaluable tool to implement powerful communications- applications. It is designed to be the base of a whole range of new protocol-stacks for networking, telephony, file-transfer, application- sharing or any other application you can think of - and even things you cannot imagine yet. The vast amount of CAPI-compliant hardware available right at this moment is probably the most persuading argument for any software-developer to base his applications on this specification. And the broad range of applications available for COMMON-ISDN-API is a key factor for every ISDN controller-manufacturer to join in and participate with his own products.

One additional argument is of cause the fact, that your products will be based on an international agreed standard, set by the European Telecommunications Standards Institute (ETSI). COMMON-ISDN-API was released as 'profil B' in prETS 300 325 Ed. 2.

For formal reasons ETSI reorganized this document, so COMMON-ISDN-API is now embodied in European standard ETS 300 838 "Integrated Service Digital Network (ISDN); Harmonized Programmable Communication Interface (HPCI) for ISDN". COMMON-ISDN-API is also embodied in ITU's recommendation T.200 "Programmable communication interface for terminal equipment connected to ISDN".