Busy verification

In a public switched telephone network, busy verification is a network-provided service feature that permits an attendant to verify the busy or idle state of station lines and to break into the conversation.

A 440 Hz tone is applied to the line for 2 seconds, followed by a 0.5 second burst every 10 seconds, to alert both parties that the attendant is connected to the circuit.

单词	Busy verification
释义	Busy verification 英语百科 Busy verification In a public switched telephone network, busy verification is a network-provided service feature that permits an attendant to verify the busy or idle state of station lines and to break into the conversation. A 440 Hz tone is applied to the line for 2 seconds, followed by a 0.5 second burst every 10 seconds, to alert both parties that the attendant is connected to the circuit.
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