User Manual

ADCP-75-179 • Preliminary Issue A • September 2004 • Section 2: Description

Page 2-14

4.2 Mounting

The 35 Watt LPA mounts within the RU outdoor cabinets and the indoor mounting shelf.

Runners on the top and bottom of the LPA mesh with tracks within the cabinet or mounting

shelf. The runners and tracks guide the LPA into the installed position. The electrical interface

between the STM and LPA is supported by a D-sub female connector located on the rear side of

the LPA. A corresponding D-sub male connector mounted at the rear of the RU outdoor cabinet

or indoor mounting shelf mates with the LPA connector. Captive screws are provided for

securing the LPA in the installed position.

4.3 Fault Detection and Alarm Reporting

The 35 Watt LPA, in conjunction with the STM, detects and reports various faults including

power amplifier fault, output power fault, temperature fault, and fan fault. Various Light

Emitting Diode (LED) indicators, located on the front panel of the LPA, turn from green to red

or yellow if an LPA fault is detected. In addition, a digital display located on the LPA front

panel provides various fault messages. The status of the LPA, the alarm state (major or minor),

and other more detailed information is summarized and reported (by the STM) over the optical

interface to the HU and also to the service interface. This information may be accessed through

the EMS software GUI, the NOC/NEM interface, or the SNMP interface.

4.4 Powering

The LPA is powered by various DC voltages which are supplied by the STM over the electrical

interface provided by the D-sub connectors and wiring harness mounted within the RU outdoor

cabinet or indoor mounting shelf.

4.5 Cooling

Continuous air-flow for cooling is provided by a pair of fans. In the previous version of the LPA,

fans are mounted at the front and the rear side of the LPA housing. The front fan pulls cool air

into the module and the rear fan exhausts heated air out of the module. In the new version of the

LPA, two front mounted fans pull cool air into the module. The heated air is exhausted out the

back of the module. An alarm is provided that indicates if a high temperature condition (>50º C/

122º F) occurs or if a fan failure occurs. The fans may be field replaced if a failure occurs.

4.6 User Interface

The LPA user interface consists of the various LEDs, message displays, and switches that are

provided on the LPA front panel. The LPA user interface points are indicated in Figure 2-6 and

described in Table 2-3.