| 摘要 |
PURPOSE:To transmit a signal of a telephone set to a relay line directly without using a retransmitter in using a push-phone, by inserting an attenuator to a transmission line until a called tone responds at the transmission of relay line. CONSTITUTION:When an extension subscriber (SUBA) hooks up a handset and dials a relay line transmitting number, this call is connected to a bi-directional trunk BWT via an exchange switch, the channel of the caller SUBA is extended to A1 and B1 terminals and connected to a carrier terminal station device MOD. Since no earth is given to a terminal RG2 from a remote station until a called tone (SUBB) responds, relays J, K, G are not operative, and an attenuator PAD- A is inserted to a channel TA of the transmission side. When the SUBB responds, earth is given to the RG2 terminal, the G relay is operative and the PAD-A is eliminated from the line TA. |
