I remember reading somewhere -- I think it was in a CIA or NSA briefing paper -- that during Desert Storm, the Iraqis refused to communicate by radio because they were too scared of the U.S. codebreakers. Instead, they used landlines, which they thought were more secure.

Is this in any way true and, if so, is there a source for it?

(I have no security clearance with anything top secret, so if this is true it's out in the open.)