My dog doesn't react to familiar voices over the phone at all. The compression and reproduction of audio, while fine for humans, definitely doesn't work for her animal ears.
Everything is tuned for human audible range, so dogs will miss out on the higher frequency stuff. Humans did ok with POTS@8kHz with a 300-3400Hz band pass filter though. The internet says dog hearing goes up to ~ 60 kHz; most audio equipment tuned for humans won't go anywhere near that, but probably cleanly carying high frequency up to the limit of the equipment would be better than psychoacoustic compression tuned for humans.