Q26Extreme and CSD data call

I use Q26Extreme with firmware 7.46.From document AirPrime_Q26Extreme_Explanation_of_Restrictions.pdf I read at page 10 Chapter 13 - Data Commands (from Notes field) that “Circuit switch data not supported”.
What does it mean ? That CSD data call are not supported ?
Thanks in advance to anyone who will help me

Yes, you are right.
CSD data call is not supported on Q26Extreme.

Packet switched (e.g. GPRS, 3g) data is supported.