ll potential of data manage- ACD to small and medium sized businesses which would find the ment by Centrex. Standard features are being implemented on cost of a PBX-based solution prohibitive. the DMS as they are defined. The Basic Rate Interface (BRI) The DMS also allows network wide distribution of ACD groups. carries two 64kbit/s B-channels plus one 16kbit/s signalling A service organisation e.g. motor insurance, could publish one channel and delivers voice, circuit and packet switched data to directory number for inquiries, but incoming calls would be passed as many as eight terminals on one pair of telephone wires. The to an agent group located closest to the caller, reducing the cost of Primary Rate Interface (PRI) offers 30 B-channels plus one the call. It also allows calls to overflow to other groups if the first 64kbit/s signalling channel, and can form the ISDN link be- group is busy. tween a central office switch, digital PBXs, and host com- Using the calling line information passed with each call, sophisti- puters. cated applications can be developed e.g. for telemarketing or infor- mation services. This is done via a Switch to Computer Applications Since all DMS data services provide switched access, terminals Interface (SCAI), which allows the DMS to be linked to business can reach multiple hosts as quickly and easily as dialling a normal computers. These services can be used to generate extra revenue phone call. Digital Centrex provides a range of calling features as (e.g. mail-order) or save on operating expenditure (e.g. outbound well as a range of security features, such as defined customer calling to check customers are at home before sending out service groups, closed user groups, and direct inward system access auth- engineers). Further sophistication can be added by using an Interac- orisation codes, to guard against accidental or deliberate breaches tive Voice Response system, with the ACD, to provide interactive of security. routing, such as determining if the caller wants sales or service