3M MODULE A125 Installation Instructions

Noise reduction module

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Noise Reduction Module

Model A125

Installation Instructions

Description

The 3M A125 Noise Reduction board (3M part number 78-9236-6453-2) improves the inbound intelligibility of an

intercom system by reducing environmental background noise from vehicles, airplanes, noisy intersections, wind,

etc.

The 3M A125 Noise Reduction Module requires a 3M model C921BA or C922AA Base Station.

1. Remove the right-hand and left-hand top covers from the 3M base station. Be careful that the main circuit

board does not fall out of the plastic base.

2. See ***Important installation notice*** on next page before performing this step.

Plug the A125 ribbon cable onto connector J8, located at the top of the left side of the circuit board. Be careful

to support the rear side of the base station circuit board when plugging in the A125 ribbon cable.

3. Position the holes near the edge of the A125 circuit board over the plastic standoffs on the base station.

4. Attach the left-hand base station cover after configuring the A125 board, and performing the Final Checkout

Procedure.

Install the A125 board here

Figure 1. Mounting the A125 to the C921BA Base Station

Table of Contents

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Page 1 The 3M A125 Noise Reduction Module requires a 3M model C921BA or C922AA Base Station. Installing the Noise Reduction board into the 3M Base Station 1. Remove the right-hand and left-hand top covers from the 3M base station. Be careful that the main circuit board does not fall out of the plastic base.
Page 2 ***Important installation notice*** Starting with serial number 125002477, the A125 Noise Reduction Module, Internal has a wider ribbon cable plug. A limited number of these Noise Reduction Modules have two individual ribbon cable plugs. The wider ribbon cable plug(s) are too wide to fit into the blue 20-pin base station receptacle. The receptacle on the wireless base station board must be trimmed and the ends opened.
Page 3 System Configuration The A125 Noise Reduction board is configured by two jumper switches, (JMP1 and JMP2), shown in Table 1. Jumper Position JMP1 JMP2 Note: * Indicates factory default settings Mode Configuration The A125 Noise Reduction board can be configured in several different modes by using DIP switch, SW1. Following is a brief description of each mode and a DIP switch setting table.
Page 4: Troubleshooting
Status Indication The condition of the red LED on the 3M C960 base station indicates the current status of the unit. The LED can be off, blink at defined intervals, or be constantly lit. Table 3 illustrates the status indicated by the LEDs.