I’m assuming that you are having echo while using the 2-wire I/O. If this is the case you must null the 2-wire circuit while connected to your 2-wire equipment using the nulling potentiometer located at the rear of the base station along with a single wireless beltpac on only. Make sure the sidetone is off and while speaking sharply into the headset of the beltpac adjust to the least amount of echo using the nulling potentiometer. We have found that removing the termination from the 2-wire equipment and terminating at the DX200 base station reduces the echo effect. We have also found that terminating at both the 2-wire equipment and the DX200 base station will also help. But this may cause your audio to become too low due to the double termination.

With regards to your low audio concerns there are adjustments on the front panel of the DX200 for adjusting the 4-wire audio for both send and receive. The 2-wire audio adjustments are performed in the factory. Please confirm that the equipment connections for each I/O port meet the following electrical requirements: 4-Wire I/O: RJ45, 600Ω balanced, level adjustable.2-Wire I/O: XLR-3M, XLR-3F, externally-switchable RTS® or Clear-Com® mode.
If you should need to adjust the 2-wire audio there are internal potentiometers that are adjustable by a knowledgeable technician. We do not recommend adjusting the 2-wire audio level settings and changing them could require sending the base station back to HME for accurate re-adjustment.  The 2-wire audio adjustments can be done with the following potentiometers:R46 adjusts the input receive, RX, level.R57 adjusts the send, TX, audio level.