Latency and drop out during calls

[regrahc]

I have an OBi110 connected to a landline (done this way so I can dial automatically using XLite vs punching in phone #'s each time.

When I use a regular phone plugged into the OBi, voice quality is great.  When I try using XLite/OBiApp on my laptop, conversations are constantly dropping out.  Have tried several headsets and two different computers, and both the OBi and my laptop are plugged directly into my cable modem, bypassing my home router. 

Is there a way to "tune" the OBi to reduce the drop out, or is there a different softphone that works better?

Thanks for any and all assistance!