BSNLFEATURES IN EWSD Subscriber and System Features 1.1. INTRODUCTION The EWSD Digital Switching Systems offer a wide range of telephony features and supplementary services. Further capabilities can be developed to meet specific customer needs. Due to mandatory requirement of exchange of messages between the switching systems and user’s equipment, some of the services are exclusively offered to ISDN-subscribers. In case of few of the services offered to PSTN and ISDN subscribers, the implementation of services to PSTN subscribers may be partial and invocation procedure may also differ due to the same reason. 1.2. PSTN (ANALOG) AND ISDN SUBSCRIBER SERVICES The subscriber services provided by EWSD exch. for PSTN (Analog) as well as ISDN subscribers are explained as per their logical grouping: 1.2.1. Number Identification Service i. Calling Line Identification Presentation (CLIP) ii. Calling Line Identification Restriction (CLIR) iii. Calling Line Identification Restriction Override (CLIRO) iv. Malicious Call Identification (MCID) 1.2.2. Call Offering Supplementary Services i) Call Forwarding Unconditional (CFU) ii) Call Forwarding Busy (CFB) iii) iv) 1.2.3. i. ii Call Forwarding No Reply (CFNR) Call Transfer Call Completion Services Call Waiting Call Hold 1.2.4. i. i. Multi-Party Services Three party conference Multi party conference ( Add-on conference ) or Large Conference Miscellaneous Services Hot Line (Timed) 1.2.5. i. ii. Hot Line (Immediate) iii. Reminder Call / Alarm Services i. Subscriber Controlled Call Restriction Services v. vi. vii. viii. Intrusion Barring Service Trunk Offer Priority Subscriber Catastrophic Immunity ix. Distinctive Ringing for Long Distance Calls x. Subscriber Credit limit supervision xi. Screening List ( Black List or White List ) xii. Remote Subscriber Control Inputs 1.3. ISDN - SUPPLEMENTARY SERVICES 1.3.1. Charging Related Supplementary Services i) AOC-E, Charging information at the end of the call i) AOC-D, Charging information during a call 1.3.2. Group Line Supplementary Services i) Direct Dialing In (DDI) ii) Multiple Subscriber Number (MSN) iii) Closed User Group (CUG) iv) v) Sub - Addressing (SUB) CENTREX 1.3.3. Number Identification Service i. i. i. Connected Line Identification Presentation (COLP) Connected Line Identification Restriction (COLR) Connected Line Identification Restriction Override (COLRO) 1.3.4. Miscellaneous Services i) Terminal Portability (TP) 1.4. SYSTEM FEATURES 1.4.1. Signaling, Routing and Charging 1.4.2. Exchange Operation Features 1.4.3. Maintenance Features 1.4.4. Integrity 1.4.5. Patch System Software Up-gradation and Administration 1.4.6. System Configuration