Which of the following techniques is not an access method in JTIDS/MIDS?

The correct answer is identified as an option to not be an access method used within JTIDS/MIDS systems. The Joint Tactical Information Distribution System (JTIDS) and Multifunctional Information Distribution System (MIDS) primarily operate using specific access methods to manage and share data efficiently among users.

Contention access allows multiple users to share the same communication channel dynamically but may lead to conflicts, making it suitable for scenarios where various units are trying to transmit data simultaneously. Dynamic access also refers to flexible allocation of communication resources, adjusting to the changing network demands and ensuring effective communication.

Time Division Multiple Access (TDMA) is a more structured technique whereby different users are allocated specific time slots for transmission. This eliminates the chance of interference and guarantees a performance baseline as each user has a defined period to communicate.

On the other hand, cross access does not represent a recognized communication method in the JTIDS/MIDS context. Although it may imply a form of communication or a routing mechanism, it does not align with the established access methods like the others listed. This makes it the correct choice for the question, as the other methods directly relate to the operation and efficiency of communication within these tactical systems.