Ah SATVOICE, the Emperor’s not so new clothes. I totally get why it might be liked by folks in the flight deck, but my God is it inefficient and unreliable for us on the ground.
Best place to get numbers as mentioned is in AIP or regional equivalent of NAT DOCs. We occasionally have iridium users who obviously just Google the number for our center. Thus they get through to reception and need to be transferred into Operations on a handset…..somewhere in the room nowhere near the controller they need to talk to.