The reason why these transfer rates are needed is that business communications and office automation through workstations and LANs is expected to make severe demands on the communications network. In particular, the B-ISDN with its ATM technology will be an efficient way to implement multimedia communications, with video information added to the conventional voice and data information. Also in the background is recent progress in optical technology. As shown in the table, B-ISDN services will be available in two broad categories, interactive and distribution. The following offers some examples of services that could be provided under these categories.
Interactive services feature bi-directional communications between terminals.
Communications can be simultaneous, as in telephone conversations, monitoring by remote cameras or TV conferences, or non simultaneous, as in the case of store-and forward message transfer services or database retrieval services. Distribution services refer to television broadcasting and other kinds of services in which information is passed from a provider to an indeterminate number of recipients. As related above, the B-ISDN can offer a wider variety of services than conventional communications networks. But another of its outstanding characteristics is a new approach to transmission speeds, multimedia communications and quality control. CBR services are provided at a fixed transmission speed.