SignalStrength values: what's the difference between cmda and evdo?

On a Verizon phone, a Motorola Droid X2, if I get the signal strength with a SignalStrength object and look at its values, bot开发者_运维技巧h the cdma and evdo values appear valid.

If I print out a signalStrength.toString():

09-09 11:48:00.678: INFO/ConnectionStatusAndroid::onSignalStrengthsChanged(4773): *** Signal Strength:SignalStrength: 99 -1 -87 -70 -63 -1 5 cdma 0 0 0 0 0 0

If the phone gives out apparently valid values for both cdma and evdo, then what's the difference?

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EV-DO is a CDMA-based 3g standard, the other is one of the CMDA-based 2g standards.