I currently have a Linksys SPA3102 and am finding the call quality is very poor. I've spent hours looking on the internet and trying different tweaks to the SPA/PSTN gain, echo cancellation and suppression settings, but it seems basically impossible to get decent call quality. Can anyone recommend a good quality FXO gateway - I only need one port, but would be prepared to pay for decent call quality even if it meant having redundant extra FXO ports. I've seen mentioned the Grandstream 4104 and the Patton 4114, but with sometimes contradictory reports about quality. Could anyone share their experience/recommendation ?