Installing the NAE/NIE Technical Bulletin
17
Wiring Considerations
N2 Bus (NAE Only)
Table 6 summarizes the rules and maximum allowances for installing
the N2 Bus. For more information on N2 Bus rules, and for details on
N2 Bus applications, see the
N2 Communications Bus Technical
Bulletin (LIT-636018)
. For information on setting up your database
with an N2 Bus integration, see
System Configuration Tool Technical
Bulletin (LIT-1201534)
.
Table 6: NAE N2 Bus Rules
Category
Rules/Maximums Allowed
One or two N2 Buses per NAE
General
Only daisy-chained devices (with maximum stub length of 3 m (10 ft) to any device
Number of Devices
100 devices per N2 Bus (up to 200 TC-9100s exceptionally) with no more than two
repeaters between NAE and any device and maximum of 50 devices between
repeaters
1,500 m (5,000 ft) twisted pair cable without a repeater
4,500 m (15,000 ft) twisted pair cable from NAE and the farthest N2 device (three
segments of 1,500 m [5,000 ft] each, separated by repeaters)
Line Length and
Type
2,000 m (6,600 ft) between two fiber modems
Cable
Solid or stranded 18 AWG recommended (26 AWG twisted pair or larger is
acceptable)
Two EOL (220 ohm resistor) or switched EOL, one in each end device per segment
(preferred)
Terminations
One EOL (220 ohm resistor) or switched EOL in one end device per segment
(required)
The NAE has two End-of-Line (EOL) switch blocks, one for each N2
Bus. Each block has two slide switches to switch in a 220 ohm EOL
resistor and 1200 ohm bias resistor to terminate the N2 Bus (shown in
Figure 12). The EOL resistors are switched in when the switches are
set towards the side marked ON. The NAE is delivered with the
switches in the ON position.
O N
1 2
eol
Figure 12: N2 Bus EOL Switches in the Default Position
