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INTRODUCTION:   

 

 

 

 

 

 

REI 

 
Thank you for purchasing the CMA-100 Countermeasures Amplifier.  When doing a 
Counter-surveillance investigation, it is important to analyze all of the wiring in the 
environment to ensure that building wiring is not being utilized to transport audio or 
video information. This wiring may include but is not limited to AC power lines, 
telephone wiring, LAN wiring, security system or access control wiring, intercom 
speaker wiring, heating and cooling wiring, etc… The main reason for analyzing suspect 
wiring is that a microphone that is well shielded is very difficult to detect with an 
ORION.  Also, an OSCOR will not detect a hard-wired microphone because there is no 
radiated signal. The CMA-100 is an ideal tool to analyze miscellaneous wiring for audio 
content.  Some scenarios of problems that can be discovered with a CMA are: 

1.  Utilizing an unused pair of telephone wires or LAN wiring to connect directly to a 

shielded microphone in the suspect environment 

2.  A phone set with a hot microphone or hot earpiece used as a microphone.  
3.  Microphones can easily be installed in miscellaneous wiring such as thermostats, 

motion detectors, Intercom speakers, AC Junction boxes, etc… 

4.  Many digital phone systems have audio leakage that occurs on the digital lines 

due to cross talk within the phone set. A CMA can be used to expose this type of 
vulnerability.  

 

The CMA-100 can be connected to wiring (assuming that the AC voltage does not exceed 
40 VAC or 250 VDC) and the audio content can be accessed.  Furthermore, if there is 
video content on the wiring, the video synchronization pulses can be heard and identified 
through the CMA. 
 
The CMA-100 is a high gain audio amplifier that is used to detect and identify certain 
types of surveillance devices connected to building wiring including telephone wiring, 
LAN, Server systems, de-energized AC power, etc....  
 
This  multi-functional  amplifier  has a  built  in  AC/DC  digital  voltmeter,  selectable  audio 
filters, and an extremely wide dynamic range.  
 
Balanced  and  unbalanced  high  impedance  input  provides  connectivity to  a wide  variety 
of suspect wiring.  
 
The  CMA-100  also  provides  a  bias  voltage  adjustable  between  –14.5V  to  +14.5V  DC 
that is used to possible activate devices that are voltage or current sensitive.  
 
All  of  these  functions  employ  a  sophisticated  automatic  gain  control  circuitry  that  is 
unmatched by any other audio amplifier. 
 
This instruction manual covers the operation and specifications of the CMA-100. 

 

 

Summary of Contents for CMA-100

Page 1: ...CMA 100 Counter Measures Amplifier Owner s Guide Research Electronics International 455 Security Place Algood TN 38506 931 537 3359 www reiusa net...

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Page 3: ...s motion detectors Intercom speakers AC Junction boxes etc 4 Many digital phone systems have audio leakage that occurs on the digital lines due to cross talk within the phone set A CMA can be used to...

Page 4: ...uipment or user it is NOT recommend maintaining connection to such circuits Extreme care should be taken when connecting the CMA 100 to an unknown electrical source Always check line voltage with a mu...

Page 5: ...2 Power Switch 3 Filter Selector 4 Gain Selector 5 Test Lead Cable Connector 6 Line Out Jack 3 5mm 7 Meter 8 Input Attenuator Indicator 9 Line Bias Indicator 10 Line Bias Switch 11 Line Bias Voltage...

Page 6: ...quencies above 320Hz and attenuation of lower frequencies The effect of this filter is to remove low frequency noise such as AC power line noise 4 The Gain Selector gives the user two operation modes...

Page 7: ...rator is turned on 10 The Line Bias Switch will turn the Bias Generator on or off 11 The Line Bias Voltage Adjust will control the magnitude of the bias voltage The mid position will generate 0V Turn...

Page 8: ...volts Strong Signal Interference If the input is attached to an AC voltage greater than 40 volts the audio content will be masked Signal Frequency Interference Wiring in a building is very susceptibl...

Page 9: ...ing sound within physical structures Over voltage protection If the CMA s input voltage limit is exceeded then damage will most likely occur that will make the CMA require repairs The CMA case is isol...

Page 10: ...Hz LOW PASS FILTER 25 Hz to 3 2 kHz BAND PASS FILTER 320 Hz to 3 2 kHz HEADPHONE AUDIO OUTPUT 16 ohm 105dB SPL limited LINEOUT AUDIO OUTPUT 600 ohm BIAS CONTROL 0 to 14 5 VDC 5 mA max Over current pro...

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