PSTN & MOBILE N/W PROVIDERS IP backhaul Corporate use
HISTORICAL MILESTONES 1974: IEEE published a paper 1985: creation of NSFNET. 1994: invention of VOIP 1995: Standardization for VOIP 1996: Voice comm. 1993: First soft switch 1999: Open source PBX 2004: VOIP service providers proliferate.
PSTN Consists of Fiber optic cables , telephone lines etc. Single address space Single numbering plan
ISDN Simultaneous digital transmission Integration
CALL BILLING SOFTWARE User wise rights declaration Party maintenance Extension details Security Scanned registration forms Shifting Reprocess calls
CALL ACCOUNTING SYSTEM Records events Detection of calls Call logging
WORKING OF CALL ACCOUNTING Collects data Attachment of revenues Sends information Storage of data Collection of voice data
CALL LOGGING Collection of phone call data CDR data To generate geographical reports
CALL SIGNALLING To set up a connection Authentication Minimization of risks
ADVANTAGES OF EPABX Cost reduction Predetermination of calls Software accomplishment Portability Flexibility
DISADVANTAGES OF EPABX Needs electric power Low installation & configuration Increase in long distance charges Low mobile workforce
APPLICATIONS Call center Computer support center IT response center Technical support center Information center Resource center
FUTURE SCOPE Include VOIP PBX Additional features
CONCLUSION A modern PBX from the equipment point of view , is much simpler then the older electromechanical systems . Most of its sophistication is built inside the chips that actually carry outside the work. The switching matrix tends to be quite small ,& new opportunities are available for convenient design of user terminals. Trunk circuits, going mostly to obsolete (2-wire analog) central offices and to analog long-haul tie-trunks, still have to meet the outside world on its own terms, but even they, while they are still with us, take advantage of PBX control and component sophistication. Fortunately, new standards may soon let us leave the analog world behind.