asterisk users - Feb 2007 - TDM2402E routing incoming calls out to cell phone low volume

I have a TDM2402E with asterisk 1.4.0
Incoming calls that route back out a port have LOW volume
I am presently using an rxgain and txgain value of 4.0

What might I try different here?

I thought a saw somewhere where it wasnt recommended to go higher that 5.
How can I bring up the audio level to the cell phone?

Thanks,

Jerry