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Special Agent "Listening" Device

Featured Artifact

Before the Department of Homeland Security was operational and investigators were transferred to ICE (Immigration and Customs Enforcement) in 2003, Special Agents tracked down smugglers and other Customs violators for the U.S. Customs Service and secured evidence against them.

Among the equipment in their investigative arsenal were “trap and trace” wiretap devices. This pen register/phone tap was a key law enforcement tool. The pen register was old technology stemming from the telegraph era; the battery-operated register recorded phone numbers dialed out of a specific telephone line onto ticker tape.

The tap was not an audio recorder, but rather allowed Special Agents to plug in headphones and listen in on phone conversations. They wrote down what they heard in notebooks, which were accepted as evidence in court along with the register tapes and accompanying Special Agents’ testimonies. Pen Registers like this one were still used by Customs into the 1980’s, when they were replaced by dialed number recorders (DNR) that were smaller, quieter, and computerized.

Photograph of a pen register

Object ID# 2012.48.1
Manufactured by JH Bunnell Co., Brooklyn, New York, c.1960.
Wooden box with plastic handle containing a pen register with battery, and device for plugging in headphones and connectors to listen in on telephone calls. A drawer within the case contains additional register tape, two keys for winding the pen register, and a bottle that probably contained machine oil.

This pen register was transferred to the historical collections at Customs Headquarters in Washington, D.C. by Special Agent in Charge Henry W. Petersen of the New York office.

Last Modified: Dec 11, 2019