ISDN – INTEGRATED SERVICE DIGITAL NETWORK

1. It was introduced in India by 19962. CCS7 signaling is a must need for ISDN3. Simultaneous Voice and Data call is allowed in ISDN ( atleast two)4. Two types of broad band

a. Narrow band ISDNb. Broad band ISDNc. Universal ISDN

5. Classification of Basic ISDN Service based on accessa. BRI ( Basic Rate Interface)b. PRI (Primary Rate Interface) {Multi access + High speed access)

6. ISDN can simply defined as “Network based on digital telephone Network”7. Service rendered by ISDN

a. Packet switching serviceb. Circuit switching servicec. Leased switching service

8. ISDN can be interfaced with analog telephone, digital telephone, FAX, Video terminals, personal computers etc

9. summarization of ISDN definition : 1. It offers variety of service such as telephone, data and image transmission in one network 2, ISDN handles all information digitally

10. Hardware components needed 1.NT (Network Terminator) 2. TA (Terminal Adaptor) mainly called CPE (Customer Premises Equipment)

11. Channels in ISDN 1. Bearer channel – B channel – 64 Kbps

It is used to carry information such as Voice of packet data at a data rate of 64 Kbps. It does not carry signaling info

2. Data channel – D channel – 16 pr 64 KbpsIt usually carries Signaling information such us origination of call termination of calls for circuit switching and packet switching.It allows multiple logical channels in packet switching.

12. H – channel is nothing but it carries high speed user info. a. H0 – 64*6 =384 Kbpsb. H1 – 64*24 =1536 Kbpsc. H2 – 64*30 = 1920 Kbps

13. Types of Interfaces used “STUR’ i.e., S,T,U,R14. Reference points – NT1,TA,NT2,TE1, TE2,U,S,T

NT1 – Layer I functions Circuit termination, timing and supply of electricity NT2 – Layer 2 functions such us protocol control pbxTA – Terminal AdapterTE1 – ISDN Terminal directly connected to S Point

TE2 – Non ISDN terminal connected to TAS – 4 Wire physical device which is connected between NT2 and TE1 or NT2 and TA.T – 4 Wire Interface between NT1 and NT2R – 4 wire interface between TA and TE2U – 2 wire subscriber Line

15. Multi service – Multiple services like ISDN terminals, pc, Fax (Digital & Analog)

16. Multi point – up to 8 connections can be connected with NT 17. American standard primary group interface 1.544 Mbps (23B+D)18. Europe standard primary group interface 2.048 Mbps (30B+D)19. The channels are bundled with Time division Multiplexing20. Subscriber line interface – Logical structure and Physical Structure21. Logically a BRI consists of 2B+D and PRI consists of 30B+D22. Physical structure consists of TCM ( Time compression Modulation) and

Echo Canceller23. EC – due to usage of Hybrid ckt (2W to 4W conversion) a loop back leakage

signal produces echo. EC is used to avoid it between TX and RX lines.24. Cross talk with same direction – Far end cross talk25. Cross talk with opposite direction – Near end cross talk26. TCM – another method to avoid Echo.27. with this system the Transmission and Reception are done at different time

slots28. TCM needs higher bit rate29. TCM system transmits signals from NT through mutual time-sharing30. U interface table

System baud rate distance

EC system (AMI) 160 Kbps 5KmEC system(2B1Q) 80 Kbps 7KmTCM system 320 Kbps 50 dB (7Km)

UT

R

TE1

TE2

NT2

TA

NT1 ISDNS

S

31. Supplementary services:1. Call hold2. DDI (Direct Inward Dialing)3. MSN (Multiple subscriber Number)4. Sub addressing5. CLIP6. CLIR7. TP (Terminal Portablity)8. CUG (Calling User Group)9. UUS (User to User Signaling)