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68 ICX (International) issued October 2000 ICX-50-700
Chapter 3. System Features Section 700 - Operation
Trunk Interface - ISDN-PRI
The System supports ISDN PRI with the VB-44540 ISDN PRI Interface unit. The VB-44540 is a T/S-
Point ISDN PRI that supports 30B (for UK) or 23B (for HK) (bearer) channels and 1 D (data) channel
(30B + D; 2M) (23B + D; 1.5M). This unit connects to an ISDN DSU.
Up to 3 units may be installed in a CCU if you use full channel (30B + D)/(23B + D or 24B). A
maximum of 18 units may be utilised in a fully equipped system. When all 30 or 23 channels on a unit
are utilised in one card, four or three slot positions are required.
Hardware Requirements
•N/A
Considerations
•N/A
Trunk Interface - Loop Start
The VB-44510UK Loop Start interface unit supplies 8 loop start analog exchange line circuits. In
addition, the VB-44510UK Loop Start interface unit may alternatively be used to connect to loop start
exchange lines.
Hardware Requirements
• VB-44510UK Loop Start Card
Considerations
•N/A
Trunk Ringing Types
Description
Several types of trunk ringing are available for the System including the following:
• Direct Dial Inward (DDI) Ringing
• Direct Line (DL) Ringing
• Direct Inward System Access (DISA) Ringing
• Multiple Ringing
These ringing types may be used in any combination in the System.
DDI Ringing
DDI Ringing allows calls on a common trunk to be directed to ring to a specific extension or group of
extensions, etc. based upon the final digits dialled. These final digits are received from the DDI trunk
and compared to a DDI Table that determines where the calls should ring. Depending on the
assignments in the DDI Table, names or trunk numbers are displayed. (Names can be up to 10 digits
long.)
DDI Ringing can be very useful by sending calls directly to a specific extension, hunt group, etc.
based upon the number dialled. Since a relatively small number of trunks handle the DDI calls, this
can be more cost efficient than DL trunks or attendant group answering and transfer. (DDI may send a