Altigen AltiWare ACC 5.2 Administration Manual page 171

Parameter
Transmit to CO
(dB Gain)
Description
Slide setting adjusts the gain from the trunk to the CO from
0 dB to -7 dB for every Quantum Trunk channel.
0 dB
The default setting is
to change this setting.
Caution! Setting the volume too high will cause distortion in
voice quality and/or missed DTMF digits.
AltiWare ACC 5.2 Administration Manual 159
Chapter 12: Trunk Configuration
, and it is highly recommended not