| 摘要 |
PURPOSE:To attain release of lockout state by transmitting automatically a lockout state signal tone to a subscriber in the lockout state in an automatic exchange. CONSTITUTION:A busy tone BT is transmitted to a subscriber telephone set TEL during the lockout state. Since a HOW relay is released after the consecution of prescribed time, the budy tone BT is switched into a lockout state signal tone HOW, which is fed to a subscriber telephone set TEL. When the subscriber hooks on a handset, the transmission of the lockout state signal tone HOW is stopped, the lockout state signal tone HOW is switched into the busy tone BT and the system is restored to the normal state. |
