Technical Description
PFU3 B provides input low voltage protection, transient protection, soft start
and electronic fuse to limit surge currents at start-up, or overload currents
during short circuit.
3.2.2.2 Cooling
Forced air-cooling is always required and provided by FAU2, which holds two
internal fans.
Air out
9707
Air in
07/NPU
06
05
04
03
02
08/FAU2
01/PFU3
00/PFU3
PFU3
PFU3
F
AU2
MMU2 E 155
MMU2 F 155
NPU3
E1/DS1
E1/DS1
LTU3 12 1
E1/DS1
Figure 13 Airflow in AMM 6p
The air enters at the front on the right hand side of the subrack and exits at the
rear on the left hand side of the subrack.
3.2.3 AMM 20p B
The AMM 20p B is suitable for large-sized hub sites, for example at the
intersection between the optical network and the microwave network. It has
20 full-height slots, one housing an NPU1 B and two half-height slots housing
one or two PFU1.
The remaining slots can be equipped with MMU, LTU, AAU, SMU and ETU.
Protected pairs, require two MMUs in a protected (1+1) Radio Terminal, and
are positioned in adjacent slots starting with an even slot number.
A cable shelf is fitted directly underneath the subrack to enable neat handling of
cables connected to the fronts of the plug-in units.
An FAU1 is fitted on top of the subrack unless forced air-cooling is provided. An
air guide plate is fitted right above the FAU1.
AMM 20p B can be fitted in a standard 19" or metric rack. The subrack with
FAU1, cable shelf and air guide plate has a total height of 10U.
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12/221 02-CSH 109 32/1-V1 Uen A 2008-03-14
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