Important Parlay APIs include: call control, conferencing, user interaction (audio and text messaging), charging. The APIs are specified in the CORBA Interface definition language and WSDL. A major goal of the APIs is to be independent of the underlying telephony network technology (e.g. CDMA vs GSM vs landline SS7).
Parlay work historically stems from the TINA effort. Parlay is somewhat related to JAIN, and is currently (early 2003) completely unrelated to the Service Creation Community.