ISDN Standards Overview 1ISDN Standards Overview 1

General DatacommGeneral Datacomm

•E Series protocols•Telephone network standards such as E.164 for international addressing etc.

•I Series protocols•Concepts, terminology and general methods such as I.200 services etc.

•Q Series protocols•Switching and signaling standards such as;

•Q.921 describes data-link LAPD•Q.931 describes network layer

KCC 18th August 2002

General DatacommGeneral Datacomm

•PRI STANDARDS•In USA and Japan T1/DS1

•23 x 64kbps bearer (B) channels•1 x 64kbps data (D) channel

•In UK Australia & Europe•30 x 64kbps (B) channels•1 x 64 kbps (D) channel

•H channels bond multiple B channels

•BRI STANDARDS•Most countries now 64kbps few remain on 56kbps

•2 x 64kbps (B) channels•1 x 16kbps (D) channel

KCC 18th August 2002

ISDN Standards Overview 2ISDN Standards Overview 2

General DatacommGeneral Datacomm

KCC 18th August 2002

ISDN Example TopologiesISDN Example Topologies

BRI S/T

BRI U

V.35 serial

R

V.24 serial

R

BRI S

BRI S

BRI T

BRI UI S D N

BRI U

EXAMPLE SITE IN USALocal-Loop (U interface) available direct into theRouter without the need for external NT1

EXAMPLE SITE IN EUROPE/UKRouters have BRI S/T interface and connectInto Telco supplied NT1

EXAMPLE OF LARGER SITE IN EUROPE/UKRouters can connect via NT1 or via NT2 usingthe BRI S/T interfaceOr any serial device can connect through a TA

TE2

TE2

TE1

TA

NT2

NT1 TE1 with NT1 built in

ISDN BRI startup sequenceISDN BRI startup sequence

General DatacommGeneral Datacomm

KCC 18th August 2002

Line inactive

TE becomes active and signals a 7E HDLC flag (7E = “01111110”)

Network switch send frame with the A-bit set to 0 (A=0 = no activated)

TE then synchronises on three successive pairs of line code voilations

TE then starts sending physical frames

NT synchronises using line code violations

NT starts sending frames with A-bit set to 1 (A=1 = activated)

General DatacommGeneral Datacomm

BRI S/T Interface (RJ-45) Pinouts

RJ-45 pin TE NT Polarity

3 Transmit Receive +

4 Receive Transmit +

5 Receive Transmit -

6 Transmit Receive -

BRI U Interface (RJ-45-to-RJ-45) Pinouts

NT RJ-45 Wire LT RJ-45

4 Tip 4 5 Ring 5

KCC 18th August 2002

ISDN PhysicalISDN Physical