This is only a test. I repeat, this is only a test.

Tomorrow, the federal government will conduct the first-ever nationwide test of the Emergency Alert System. The government, cable companies and radio stations are trying to get the word out about the test beforehand, because some portions of it will not indicate that it is only a test.

The test is being conducted by the Federal Emergency Management Agency, the Federal Communications Commission and the National Oceanic and Atmospheric Administration.

“A national test will help federal partners and EAS participants determine the reliability of the system, as well as its effectiveness in notifying the public of emergencies and potential dangers both nationally and regionally,” a press release from FEMA stated.

The test will occur at 2 p.m. Wednesday and last between 30 and 60 seconds. Television, radio, cable and satellite broadcasts will be interrupted.

During the test, listeners will hear a message stating, “This is a test.” It could resemble the periodic, local tests with which many people are already familiar.

However, the video portion of the test on television screens will not indicate it is a test. The text at the top of the television screen might state that an “Emergency Action Notification has been issued.”

“Charter wants to ensure that all customers, specifically those that are elderly and hearing impaired, are aware this is only a test and there is no need to become alarmed,” stated a press release from Charter Communications, cable provider for Suffolk.

Currently, state-level tests are conducted on a monthly basis, and local-level tests are done weekly. However, no top-down review of the system has ever been undertaken, according to the FCC’s website.

All EAS participants must report back to the FCC on the results of the test, including whether they received the alert message and whether they rebroadcast it. FEMA and the FCC will study the results to determine where the problems with the system are and how best to remedy them.

The date and time were chosen because it is toward the end of hurricane season and before winter weather season, and so that it would occur during working hours across the United States, according to the FCC’s website.

The agencies anticipate that nationwide tests of the system now will be conducted periodically, according to the website.