General Datacomm

1. General Datacomm
ISDN Standards Overview 1
•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

2. General Datacomm
ISDN Standards Overview 2
•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

3. General Datacomm
ISDN Example Topologies
BRI S/T
EXAMPLE SITE IN EUROPE/UK BRI U EXAMPLE SITE IN USA
Routers have BRI S/T interface and connect Local-Loop (U interface) available direct into the
Into Telco supplied NT1 Router without the need for external NT1
BRI U
ISDN
BRI U
NT1 TE1 with NT1 built in
BRI
T
BRI NT2 EXAMPLE OF LARGER SITE IN EUROPE/UK
S Routers can connect via NT1 or via NT2 using
TE1
BRI the BRI S/T interface
S Or any serial device can connect through a TA
TA
TE2
V.35 serial V.24 serial
TE2
R R
KCC 18th August 2002

4. General Datacomm
ISDN BRI startup sequence
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)
KCC 18th August 2002

5. General Datacomm
ISDN Physical
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