This read-create integer, in milliseconds, indicates when a tone times out and is the primary means of determining when the tone stops; if the tone group's duration exceeds this timeout, the tone stops at the timeout instead, and a value of 0 means no timeout, so the tone plays until explicitly stopped. Admins set this to bound how long a tone can play before it is automatically cut off, regardless of its component durations. For example, setting it to 30000 stops the tone after 30 seconds even if its underlying components would otherwise continue.