NIST Special Publication 800-53 (Rev. 4)
Security and Privacy Controls for Federal Information Systems and Organizations
Physical security safeguards applied to information system distribution and transmission lines help to prevent accidental damage, disruption, and physical tampering. In addition, physical safeguards may be necessary to help prevent eavesdropping or in transit modification of unencrypted transmissions. Security safeguards to control physical access to system distribution and transmission lines include, for example: (i) locked wiring closets; (ii) disconnected or locked spare jacks; and/or (iii) protection of cabling by conduit or cable trays.
Related to: MP-2, MP-4, PE-2, PE-3, PE-5, SC-7, SC-8