The term "signs off" usually refers to the act of concluding a message, a conversation, or a broadcast. Some antonyms for this phrase could be "starts up," "continues," or "resumes." These words imply that the communication or transmission is ongoing, without any break or interruption. On the other hand, antonyms that denote an abrupt, unexpected, or premature end of a message could be "cuts off," "abruptly stops," or "abandons." In some contexts, antonyms for "signs off" might also include expressions that suggest hesitation, such as "pauses," "hesitates," or "delays." Ultimately, the choice of antonyms for "signs off" would depend on the specific context in which the phrase is used.