asterisk users - Jan 2004 - "NOTICE: Fax detected" on 3'rd DTMF digit on outgoing call to outside line.

I get the following on the console whenever I request an outside line (9+) as 
soon as the 3rd DTMF digit is pressed on the (zaptel interface) telephone 
set.

NOTICE[1226062640]: chan_zap.c:3587 zt_read: Fax detected, but no fax 
extension.

I've searched the mailing list for "FAX detected" and there is
nothing
mentioned about getting this message during outgoing calls. The error is
not fatal, but it is an annoyance as it clutters up the console.

The versions of asterisk and libraries in use are (first release):

asterisk-0.7.1
libpri-0.5.1
zaptel-0.8.0

This problem was not present until I upgraded my system to the above verisons.
Any ideas on where to start looking in extensions.conf or other config files?

Thanks
Steve.