i330 and I guess CDMA 1xRTT still not up to my standards

Now this is just stupid. From the i330 owners manual:

Can I make calls and use PCS Vision Services at the same time? You cannot use voice and data services simultaneously. If you receive a call while the data service is active, the call will be forwarded into voicemail. You can place an outgoing call at any time, but it will interrupt any in-progress data session.

I wonder if this is a brokeness of the CDMA chipset or the CDMA protocol.