No. T-Mobile 3G supports both voice and data.
T-Mobile 3G (HSPA)
•With 3G, theoretical maximum download of 14 Mbps.
•Our 3G network operates on the 1700 MHz and 2100 MHz frequencies. You'll need a phone that supports 1700 MHz and 2100 MHz to connect to our 3G network.
•On our 3G network, you can use voice and data services simultaneously.
UMTS/WCDMA is technically capable of both voice and data.