3M A125 用户手册

 

3

 

The A125 Noise Reduction board is configured by two jumper switches, (JMP1 and JMP2), shown in Table 1. 
 

* Separate microphone & 
speaker at menu sign/post 

OSM (speaker used as both a 
speaker and a microphone at 
the menu sign/post) 

* C960 Intercom 

C5000 Intercom 

      Note:  * Indicates factory default settings 

 

 

 
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. 
 

Noise Reduction:  When DIP Switch number 1 ON the inbound microphone voice signal is digitized.  On 

digitized, the noise is digitally removed from the voice by the digital signal processor and converted back 
to an analog voice signal.  The analog voice signal is then sent to the microphone input of the intercom.  
When DIP Switch number 1 is OFF the inbound microphone voice signal is digitized and converted back to 
an analog voice signal without removing any noise. The analog voice signal is then sent to the microphone 
input of the intercom.  

Echo Reduction:  Used to reduce echo for full-duplex intercom configurations.  Turn Echo Reduction OFF for 

half-duplex intercom configuration. 

Restaurant / Truck Stop Noise Reduction Level: When DIP Switch number 3 is OFF, the board is set for 

restaurant noise reduction level.  When DIP Switch number 3 is ON, the board is set for truck stop noise 
reduction level.  This provides approximately 6dB more noise reduction with slightly more voice 
dedegration. 

Hi Frequency Equalization: When DIP Switch number 4 is ON, the higher end frequencies are increased by 

3dB.  This should be set to the customer’s preference. 

 

 

1 

* Noise Reduction ON 

   Noise Reduction OFF 

2 

* Echo Reduction ON 

   Echo Reduction OFF 

3 

   Truck Stop Noise Reduction Level 

* Restaurant Noise Reduction Level 

4 

   Hi Frequency Equalization ON 

* High Frequency Equalization OFF 

5 

   Spare 

   Spare 

6 

   Test Mode (FACTORY USE  
   ONLY; DO NOT CHANGE) 

* Normal Operating Mode 

Note:  * Indicates Factory Default Settings