8
Network Communications—N2 Communications Bus
The components of the N2 Bus are the N2 Bus Submodule (NCM101/102
only), communication terminal board, repeater, enclosure, fiber optic
modem (optional), cable, and surge protector.
N2 Submodule (NU-N2B101-0)
--
The N2 Submodule is a small plug-in
unit for the NCM101 and NCM102. (The NCM401 can also use this
submodule if for some reason it is no longer used as a migration NCM.) It
is an interface device that the NCM101/102 requires to communicate over
the N2 Bus. The N2 Submodule is required for every NCM101/102 that
communicates with any N2 device, regardless of whether the N2 device is
within the same NCU or remote from the NCU.
Note: The NCM200 contains a built-in N2 interface and the NCM401
does not use the N2 Bus Submodule when the NCM401 is used for
migration applications.
Communication Terminal Board (TBC821)
--This module is the
termination point for the N2 Bus and L2 Bus. (The old TBC model,
TBC801, also terminates the N1 LAN via two coax connectors. It is shown
in Figure 10.) It allows an NCM to communicate with NEUs and ASCs.
The board is factory mounted, and is located in the upper left corner of the
5-slot and 2-slot unit, and on the left side of the 1-slot unit. Every NCU
and NEU contains a communication terminal board.
Repeater (4683-TTM-1/2)
--The N2 Bus repeater isolates and boosts the
power of the N2 Bus signal, which extends the range and increases the
number of devices that can reside on the N2 Bus. You need a repeater only
when the N2 Bus must be extended beyond 5000 feet or beyond
50 devices. The repeater actually creates a new N2 Bus segment.
(A segment is an electrically continuous daisy-chained cable between
repeaters or repeaters to End-of-Line [EOL].) In addition, the repeater
electrically isolates the two segments.
Enclosure (BZ-1000-7 or AS-ENC100-0)
--This metal box is used to
house the N2 repeater. Because 120 VAC is terminated to the repeater via
three wires, not a plug, you must install the repeater in an enclosure to
meet National Electrical Code (NEC) requirements.
Components
3 6
2 5
1 4
TB1
3 6
2 5
1 4
TB2