Communicational cohesion occurs when parts of a module are grouped together because they use the same set of inputs and outputs. If a module has different elements that have been grouped together because they access and modify the same data structure, it would demonstrate communicational cohesion.
For example, a data structure that represents the contents of a customer's shopping basket might be used by a variety of elements in a single module. The elements might calculate discounts, shipping, and taxes based on the same data structure.
This level of cohesion is moderate and usually considered acceptable.
