 are also key issues. The details obtained by the voice processing system are shown on The basic subsystems of the voice processing system are linked the operators VDU prior to the call being transferred. by two buses. The speech bus conveys caller speech to the various There are many problems associated with achieving this function- speech processing elements and voice from the system to the caller. ality, centred around the lack of integration between PABX/ACD, In advanced systems a degree of configuration of these speech paths host database and voice processing system. In an ACD for example is possible using digital cross connection switches. the call is presented to a number of operators. The first operator to The computer bus links the subsystems to the voice service appli- accept it gets the call. The information about which operator took cations processor for monitoring and control purposes. This bus is the call may not be available to the host computer to present the also used to deliver speech information to and from the voice relevant details on the correct VDU. Also the call may be put compression/ decompression module. If the subsystems are intelli- through before the VDU screen is presented. There is a wide gent, then they are down loaded with software using this bus. variation in ACD/PABX functionality between manufacturers. While there are many proprietary standards available from indi- The system functions by recording and replaying compressed vidual manufacturers there is no clear de facto standard emerging in speech from disk under the control of the voice service applications this area of Computer Supported Telephony Applications (CSTA). processor. There are two basic architectures; those based on PCs and ECMA and ANSI standards are being formulated but are not avail- those that are proprietary. PC base products, in general, address the able yet. low end of the market in terms of line size and usually focus on just one application area; proprietary architectured products on the other hardware s