reference point (RP)
- The ISDN reference points, which are defined in ITU Recommendation I.411, describe the different properties of the ISDN interfaces. These points demarcate two functional groups from each other. The reference points R, S, T, U and V are defined at the user end of the access line (for the ISDN connection). The reference point R forms the interface when the terminal is not fully compatible with ISDN. The S reference point is the interface of the terminal for special services. The T reference point forms the interface for network access, the U reference point forms the interface that defines the transmission method, and the V reference point forms the interface that defines the characteristics of the various types of access.Two reference points have been defined for signaling between two PSTNX, the Q and C reference points. Q is the reference point for logical signaling, while C is the reference point for the physical connection. An interface may be defined at the location of a reference point.
- Inmobile communications, we also speak of reference points. These are defined MMx(MultimediaMessaging) interfaces between the Multimedia Messaging Service Center( MMSC) and external components. The reference points have the designations MM1 to MM9. For example, MM1 is for communications between the MMSC and User Agent( UA), MM2 is for internal communications in the MMSC, MM3 is for those to gateways ofe-mail systems, MM4 is to relays, MM5 is for communications with the site directory( HLR), MM6 is to external databases, MM7 is to application servers, MM8 is to the reservation system, and MM9 is to the transcoder.
