We have an Audiocodes Mediant 1000. It has one FXO card with 4 analog ports connected to POTS lines. We have a Linksys SPA941 sip phone connected. The problem is the QOS is poor. Everything is connected on the same LAN so one would think that setting everything to a high quality codec would solve things but it seems the QOS stays the same (echo, and cracking noise on the line.) We have attempted to use a few different soft phones but they result in the same QOS issues. It would seems there would be some magic switch in the Mediant 1000 that will solve all the problems but we have yet to find it. Please offer suggestions on what we can tweak/check.