I had the same problem with my new Magic Jack that many of you described with your MJ's - 1) you couldn't hear the other person even though they could hear you, and 2) no caller ID.
I fixed these problems by a) turning the "handset volume" on, and b) ensuring that my computer did not go into "sleep" mode. I have a Compaq PC running Vista so the handset volume was turned on by going to settings=>control panel=>sounds, then selecting the "handset" tab, then clicking on the button that had the circle/slash on it. (I also adjusted the handset volume here, moved it up to ~60).
The other solution wasn't so obvious - when my computer would go into screen saver mode, it was also going to sleep. So I had to change the power setting to ensure it stayed on even when the sceen saver kicked in.
Anyway, my MJ is working like a champ now. I have a new cordless phone system connected to it so we access MJ from any one of 4 cordless phones in the house. I couldn't be happier!
Cured No Sound / Caller ID Problems
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