flexfax: Multitech CNG tones?

["Mr. Arlington Hewes" <tpcadmin@info.tpc.int>]

Folks,

I'm seeing some odd behaviour with the CNG (fax beep tones) my modem 
(MT28xxZDX) is sending when going off-hook to deliver a fax. They often do not 
last long enough to be detected by the destination fax, assuming it rings once 
or twice before answering. Strangely the modem will happily wait for the 
remote machine to start warbling, but will itself have gone completely silent 
after maybe one, occasionally two CNG beeps.

I want to beep for longer! ;-)

I've been through the AT command references for the MT28xxxZDX modems, with no 
hint of the parameter to twiddle, can anyone help?

-Darren