NCS -C250C Instruction Manual page 11

Microphone Impedance
Select the microphone impedance using shunts on the Impedance jumper block (J10)
as shown in these examples:
NOTE: The 200 Ohm position is marked incorrectly on the PC Board. Use the
position shown above. Also, these jumpers can be used as a supplemental
mic level adjustment if the range of the mic pot is insufficient.
Electret Supply Voltage
If the microphone is an Electret type that needs a voltage supply, install a shunt on
J9:
Auxiliary Supply Voltage
If the microphone requires a separate voltage supply to operate a preamp, DTMF
keyboard or similar circuitry, install a shunt on the AUXV block (J5) at the
corresponding microphone pin number. Also, select the desired supply voltage, 5V
or 12V using a shunt on the AUXV jumper block (J15).
Speaker Connections
For microphones with built-in speakers or for headsets, install shunts at the
corresponding pin numbers for Selected and/or Unselected Audio on the SEL AUD
block (J7) and/or UNSEL AUD block (J6).
NCS-C250C Instruction Manual Rev J
600 Ohms
Hi-Z
(DEFAULT)
Copyright © 2004-2010 New Communications Solutions, LLC
11
200 Ohms
(DEFAULT)