sign on
noun
Definitions
The time of day when a radio or television station begins broadcasting, usually after being off the air for several hours.
Example: Sign on for the radio station is at 5 a.m.
verb
Definitions
To join something, after signing.
To commit oneself, as to a project, a goal, on organization, a cause.
Example: I never signed on for this.
To begin broadcasting a radio or television signal, usually at the beginning of a broadcasting day and after being off the air for several hours.
Example: Years ago, the TV station would sign on at 5 a.m., but now it broadcasts 24 hours a day.
To log on; to start using a computer, radio, etc., or to start talking.
noun
Definitions
The username and password for logging in to a computer account.
An attempt to log in.
(more generally) An instance of signing on to something.
A person who signs on to something.