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GDK-100
DIGITAL KEY TELEPHONE SYSTEM
120
3.5.7 ISDN
wiring
ISDN boards such as BRIB, STIB and PRIB contain RJ45 type jacks on each board, to connect to ISDN.
Following figure shows ISND reference point and Functional group,
Reference point: Theoretical point to classify the functional unit
1. V-point: PX line
2. U-point: Subscriber line
Subscriber line between public exchange and NT1 (Network termination), 2wire and 4-5Km
distance
3. T-point: ISDN Trunk line
Trunk line for PBX between NT1 and PBX system, 4wire and 1Km max distance.
4. S-point: ISDN standard user interface
Standard point for ISDN terminal connection, physically same as T-point, multiple connection
possible.
5. R-point: X or V series terminal interface.
Reference point between Terminal adapter and non-ISDN terminal connection
Functional Units
1. NT1: Network Termination
2. NT2: Protocol Handle, PBX
3. TE1: Standard ISDN interface TE
4. TE2: Non-Standard ISDN interface TE
5. TA: Adapter for non-standard ISDN interface
ISDN
PX
(LT)
ISDN
or
PC
G4-Fax
S
V,X
Terminal
SLT
NT2
TA
ISDN-
TEL
NT1
NT1
U
U
T
S
R
V
The position of GDK-
System
Figure 3.5.7.a
ISDN Reference Points and Functional Group