3M A121 - Manual
3M A121 – Manual, read for free online in PDF format. We hope this helps you resolve any issues you may have. If you have further questions, please contact us through the contact form.
Table of Contents:
- Page 2 – Mode Configuration; Restaurant/Truck Stop Noise Reduction Level:; Status Indication Table
- Page 3 – Troubleshooting; Problem Possible; Wiring Diagrams; Menu Post
- Page 5 – Figure 4. Wiring for 3M D15/D30 Intercom
- Page 6 – A121 Noise Reduction Module
- Page 7 – Needed for HME
- Page 9 – Center
Noise Reduction Module
Model A121
Installation Instructions
Description
The 3M Noise Reduction Module (3M part number 78-9236-6403-7) improves the inbound intelligibility of an
intercom system by reducing environmental background noise from vehicles, airplanes, noisy intersections, etc.
Additional Material Required
•
18 - 22 AWG twisted - shielded pair audio wire
•
2 mounting screws and appropriate wall anchors
Important:
The 3M Noise Reduction Module should be mounted no more than 3 feet from the intercom or base
station.
System Requirements
The 3M Noise Reduction Module requires a system with a separate outside microphone and speaker.
The A121 will
not function with an intercom system configured to use a single speaker as both the microphone and speaker
. The
A121 will work in conjunction with most dynamic microphones and speaker/microphone assemblies.
System Configuration
The 3M Noise Reduction Module configuration is controlled by two jumper switch (JMP1 and JMP2) settings.
JMP1 is used to set the appropriate gain for the MENU MICROPHONE.
JMP2 is used to match the A121 output level to the input of the intercom system.
Jumper
Position
Position A
Position B
JMP1
* Separate microphone
& speaker at menu
sign/post
Do not use this position
JMP2
* 3M Intercom
HME Intercom
Note:
* Indicates factory default settings
Table 1. 3M Noise Reduction Module Jumper Settings
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Summary
2 Mode Configuration The 3M Noise Reduction Board can be configured in several different modes by setting DIP switch, SW2. Following is a brief description of each mode and a DIP switch setting table. Noise Reduction: With SW2 number 1 ON, the inbound microphone voice signal is digitized. The noise ...
3 2. If the A121 is in a half-duplex system, set SW2 number 2 OFF and proceed to step 3. If the A121 is in a full-duplex system set SW2 number 2 OFF. Speak into the headset mic or intercom mic. The echo should increase. Turn SW2 number 2 back ON. The echo should decrease. 3. Set SW2 number 3 for app...
5 Menu Post To Vehicle Detector MENU SPKR ALT ALERT ALERT OUT MENU SPKR SHIELD MIC MIC AUDIO OUT 3M Base Station MENUSPEAKER MENUMIC COM 12V UNREG VEH DET MENUSPKR MENUSPKR MENUSPKR MENUSPKR SHLD SHLD MIC IN MIC OUT 1 2 3 4 5 5 4 3 2 1 MIC OUT MIC IN MENU INTERCOM COM MIC IN VEH DET MIC IN SHLD SHLD...
