No carrier

[Julene]

The [error message] given by a modem when the telephone line carrier signal is lost. In the days of [BBSs] this was a frequent occurrence, often at the very moment someone was typing a sentence. Loss of signal would cause a string of garbage characters to be displayed to the recipient.
In later years this gave rise to an unending joke, depicting someone getting forcefully interrupted or otherwise cut off the internet, out of spite, in the middle of a particularly boring thought, irritating tirade, or some [Famous Last Words].