Clear-Com HLI-FBS - Manual (Page 143)

Because the R, L and C controls interact, you may have to adjust these controls
several times to minimize the test tone / achieve a deep null.
Note: The null circuit on the CCI-22 is effective on line lengths between 0 - 4000
feet (1200m) with impedances in the range of 120 to 350 ohms. Nulling can
reduce local audio in the received signal by < 30 dB over the 200 Hz - 8 kHz
frequency range.
Tip:
For more information on the CCI-22 nulling circuit, see the CCI-22 Manual.
4) If necessary, adjust the In / Out level controls on the CCI-22 (Send and Recv,
located on the front panel next to the R, L and C nulling controls).
Note: The Send level control affects the level of the audio signals from the
Eclipse Matrix to the external party-line, and the Recv control affects the level of the
audio from the party-line into the matrix. The Send and Receive controls have a
range of ± 13 dB.
Tip:
For more information about managing the HelixNet to Eclipse connection in EHX, see your
EHX documentation (including Help).
143 HelixNet Partyline User Guide