I wish I knew the answer to your questions, but I don't. All I know is that you can lose 1x, 3G, 4G or all data and still have a strong -60dbm signal.
I suspect that the data is riding on another signal (called a carrier in AM radio) and apparently you can have a strong "carrier" and it will work for voice even without any data information riding on it. I know I'm using the wrong terms for the type of signal/modulation that the TBolt is using for this analogy. For one thing, even with FM, nothing is literally "riding" on a signal (that only happens in AM - Amplitude Modulation). With FM, for example, the entire "carrier", if you will, is changing frequency as modulation occurs (Frequency Modulation).
To understand this you might want to imagine a radio station sending out a strong signal that your radio has easily tuned into, but the DJ is not saying anything into the mic. You have silence, but a strong locked on signal. In this analogy the DJ's spoken voice would be the data component.
Another way of looking at this TBolt RF issue is that the Rodio station is strong, but the TBolt can't de-modulate the DJ's speech. Or, that DJ isn't talking at all. Kinda hard to say from our side only. You have to know what the tower/signal is doing as well as what you are seeing on the TBolt side.
-Frank
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