NEC NEAX 2000, Programming Manual

Page: 929 / 1200

ND-91285-001(E)
DECEMBER, 1999
Page 147
Revision 1.0
(1/1)
DIRECT DIGITAL INTERFACE (DDI)
GENERAL DESCRIPTION
This service feature provides the capability to connect trunks from the system directly to digital links using
either a private or public network.
STATION APPLICATION
Not applicable
OPERATING PROCEDURE
No manual operation is required.
SERVICE CONDITIONS
3. In most cases, the digital interface network provides the Source Clock to all the systems through the
lines. All the PABX operates as a Receiver Office according to the Source Clock from the network.
4. Each office is equipped with a Phase Lock Oscillator for network synchronization. Clocks from the
Source Oscillator or Digital Trunk Interface (DTI) should be connected to inputs in each PLO.
5. The DTI provides signaling interface, bipolar/unipolar conversion, frame synchronization, insertion/
extraction and alarm detection.
6. The DTI can be provided with circuit cards to interface with digital link and/or ITU-T standard net-
works.
7. The DTI cards are mounted in the AP slots of the Port Interface Module (PIM).
8. The system includes built-in PLO (Receiver Mode only) in MP card. If the system is to be used as a
Sub-Source, PLO card is required.
9. The PLO card is mounted in the AP slot of the Port Interface Module 0 (PIM0).
DS-1 SIGNAL LEVEL
PCM TRANSMISSION LINE
(24/30 CHANNEL)
SYSTEM
OFFICE
REP
OFFICE
REP
LINE
REP
LINE
REP
Digital
PABX