| 摘要 |
PURPOSE:To enable the alarm of handset-out for extension telephone set, by transmitting the howler tone to the extension line connecting howler trunk tone periodically to the extension in lockout state. CONSTITUTION:When the central control unit CC detects the extension telophone set A in handset-out after a given time, the connection between the telephone set A and busy tone trunk BTT is disconnected via the peripheral control unit SPC, and howler tone is transmitted to the telephone set A by connecting the telephone set A and howler tone trunk HWT to alarm the handset-out to the extension telephone set A in lockout state. |
