The FR4 filter is for use between receivers or transceivers, and high impedance headphones. It is a passive audio filter centered around 850 Hz. A switch is included to completely remove the filter from the headphone line for phone reception.
Specifications
Center Frequency: 850 Hz
Bandwidth at 6 dB Down: 400 Hz
Bandwidth at 60 dB Down: 2.4 KHz
Input Impedance: 2000 ohms
Output Impedance: 2000 ohms
Insertion Loss: Less than 3 dB
Size: HWD 2-1/2" x 4-3/4" x 6"
Shipping Weight: 1 lb 12 oz
Finish: Baked enamel case, molded plastic side panels with wood grain inserts