What is NOT a consideration prior to classified transmissions over secure telephone devices?

When dealing with classified transmissions over secure telephone devices, considerations primarily focus on ensuring confidentiality and maintaining the integrity of the communication. Proper encryption methods play a crucial role in encoding the information to protect it from unauthorized access. Similarly, identification of authorized personnel ensures that only those cleared to receive or transmit classified information are involved, thereby minimizing the risk of leaks or breaches. Verification of transmission integrity helps to ensure that the message has not been altered during transmission and remains trustworthy.

In contrast, while controlling access to the physical location is important for overall security, it is not directly related to the transmission of classified information over secure telephone devices. This consideration, while valuable for safeguarding sensitive areas, does not specifically pertain to the methods or protocols involved in the secure transmission process itself. Therefore, it stands out as the option that is not a primary consideration when preparing for classified communications, as the other options focus more distinctly on the technical and personnel-related aspects necessary for secure transmissions.