Jyrki T. J. Penttinen
The advances in telecommunications systems have facilitated numerous solutions that enrich the communications between users. Telecommunications solutions have provided ever enhanced ways also for the communications between systems (M2M, Machine to Machine).
As the actual access and transmission technologies advance, they provide a platform for ever developing applications.
Voice call continues being the most important service in the telecommunications networks. Voice call is one of the teleservices of telecommunications networks.
ITU-T defines “telephony service” in such a way that it provides users with the ability for real-time two-way speech conversation via the network .
The recommended overall support of teleservices by, for example, ISDN has the following standards: telephony (I.241.1), teletex (I.241.2), telefax (I.241.3), mixed mode (I.241.4), videotex (I.241.5), and telex (I.241.6). During the lifetime of ISDN, it can thus be noted that telephony is practically the only one from the list that has been used on a larger scale. It is worth noting, though, that ISDN can offer telephony as a basic telecommunication service, teleservice or bearer service.
According to Ref. , bearer services are fully described by prose definitions and descriptions, by attributes and by dynamic descriptions, which altogether define the service characteristics as they apply at a ...