Integrated Services Digital Network (ISDN)
533
F I G U R E 1 0 . 6
ISDN functions and reference points
F I G U R E 1 0 . 7
ISDN BRI reference points and terminal equipment
R
S/T
U
S/T
U
U
TA
NT1
NT1
ISDN switch
service
Router with
built-in NT1
ISDN
device (TE1)
Non-ISDN
device (TE2)
S/T
S/T
R
S0
U
bri0
bri0
Native ISDN interface--int bri0
Nonnative ISDN interface--int serial 0
(EIA/TIA-232, V.35, X.21)
Service provider
network
TE1
NT1
NT1
TA
TE1
NT1
TE2
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