The quality of an MSN or multiple MSN hops, and the PSTN ‘could’ introduce some degradation if something is failing, not rightly configured, or damaged. The important thing is that our connection to the PSTN is purely digital. The handoff from MSN to MSN to PSTN to our audio server is purely digital. We do not introduce noise with analog conversions. Further and most importantly is we measure MOS on a relative basis (not absolute). If audio quality degradation presents itself because of distance, it will degrade all handsets equally.