ISDN Standards Overview 1

1
ISDN Standards Overview 1
General 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
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ISDN Standards Overview 2
General 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
3
ISDN Example Topologies
General Datacomm
BRI S/T
EXAMPLE SITE IN EUROPE/UK Routers have BRI S/T
interface and connect Into Telco supplied NT1
EXAMPLE SITE IN USA Local-Loop (U interface)
available direct into the Router without the need
for external NT1
BRI U
BRI U
I S D N
BRI U
NT1
TE1 with NT1 built in
BRI T
EXAMPLE OF LARGER SITE IN EUROPE/UK Routers can
connect via NT1 or via NT2 using the BRI S/T
interface Or any serial device can connect
through a TA
BRI S
NT2
TE1
BRI S
TA
TE2
V.24 serial R
V.35 serial R
TE2
KCC 18th August 2002
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ISDN BRI startup sequence
General Datacomm
Line inactive TE becomes active and signals a 7E
HDLC flag (7E 01111110) Network switch
send frame with the A-bit set to 0 (A0 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 (A1 activated)
KCC 18th August 2002
5
ISDN Physical
General Datacomm
BRI S/T Interface (RJ-45) Pinouts
BRI U Interface (RJ-45-to-RJ-45) Pinouts
KCC 18th August 2002