asterisk users - Feb 2006 - DATA calls answered by IVR, but I don't want that

When incoming DATA call arrive on ISDN BRI, Asterisk recognise that this
is DATA call, but behaving like it is VOICE call: Answering call,
playing IVR messages...

How to stop that? I want that only VOICE calls are answered by Asterisk
IVR, and DATA/FAX to be ignored.

(I'm using Asterisk 1.2.1 Brisftuffed 0.3.0-PRE-1f,  ZapHFC)

-- Accepting data call from 'XXXXXXXXXX' to '3001' on channel
0/2, span
1
-- Executing Answer("Zap/2-1", "") in new stack
-- Executing BackGround("Zap/2-1", "ivr_intro") in new stack
...