Executives and security personnel may periodically inspect these seals themselves. Broken seals indicate an intrusion, while missing seals indicate a switch of telephone sets. Treat either condition as a suspicious incident. Inspection of Telephone Wiring. Wiring associated with the telephones under test are inspected for attachments, and damage.
Damaged wiring is often the only evidence of a prior wiretap.
Inspection of Junction Blocks. Junction blocks are where telephone wires connect to each other in the building. These connected wires form a path between the telephone instrument and the on-premises, telephone switching equipment. Junction blocks are an easy, and relatively safe, place to attach a wiretap device. This type of common attack is called a direct, or bridge, tap.