WASHINGTON — A 911 recording that contains a sound for hearing impaired users that most people associate with fax machines caused confusion for people trying to get help for a man who went into cardiac arrest on Easter Sunday in Prince George’s County, Maryland.

Multiple people who tried to report a man in need of urgent medical attention interpreted the loud tone at the end of the 911 call center’s recording as a failed call, NBC Washington reported.

Despite the warning before the tone, “Do not hang up,” the panic and pressure of the situation caused a number of callers to misinterpret the message:

By law, the 911 greeting in Prince George’s County contains the sound for hearing impaired users.

The tone is becoming a concern, as another issue was raised about a month ago, a 911 call center representative told NBC Washington.

Now, officials are warning callers not to hang up when they hear the tone.