User Manual

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

Page 2-8

3 SPECTRUM TRANSPORT MODULE

The STM, shown in Figure 2-3, provides the following basic functions:

• Provides an RF interface (antenna port) for the remote antenna(s).

• Provides an optical interface for the HU.

• Converts the digitized forward path optical signal to digitized RF signals.

• Converts the digitized forward path RF signals to two composite RF signals.

• Digitizes the two reverse path composite RF signals.

• Converts the digitized reverse path RF signals to a digitized optical signal.

• Provides an RS-232 interface for connecting a local EMS computer.

• Provides an RS-232 interface for an auxiliary communications link with remote equipment.

• Transports alarm, control, and monitoring information to the HU via the optical interface.

• Accepts AC power input and battery power input.

• Accepts external alarm input.

3.1 Primary Components

The STM consists of an electronic circuit board assembly, power supply, quadraplexer, and fan

assembly that are mounted within a powder-paint coated sheet metal enclosure. The metal

enclosure provides a mounting point for the electronic components and controls RF emissions.

Except for the fan unit, the electronic components are not user replaceable. The STM is

designed for use within the RU outdoor cabinet or indoor mounting shelf. Except for the LPA

interface connector, all controls, connectors, indicators, and switches are mounted on the STM

front panel for easy access. A carrying handle is provided on the front of the STM to facilitate

installation and transport.

19 ALARM OUTPUT Screw-type terminal

connector (14–26

AWG)

Connection point for an external alarm system.

Includes normally open (NO), normally closed

(NC), and common (COM) wiring connections.

20 FWD (PORT 1) SC connector

(single-mode)

Output connection point for the forward path

optical fiber.

21 REV (PORT 2) SC connector

(single-mode)

Input connection point for the reverse path pri-

mary optical fiber.

22 Chassis ground stud Connection point for a chassis grounding wire.

Note: A more detailed description of LED operation is provided in Section 4.

Table 2-1. Host Unit User Interface, continued

REF

USER INTERFACE

DESIGNATION

DEVICE

FUNCTIONAL

DESCRIPTION