| 摘要 |
PURPOSE:To specify toll origination as to nighttime origination from a nighttime direct telephone set, by providing the circuit of a nighttime switching device to a central office incoming-outgoing trunk in a private branch exchange. CONSTITUTION:When a nighttime direct telephone set SUB originates in the daytime, a trunk line is acquired through the contact ns of a normally operating relay in a central office outgoing-incoming trunk CBWT, a line circuit LRG, a line frame LLF, a contact ns, and a unit COTRSAU having an added central trunk register sender to check dial pulses from the telephone set SUB by a register sender CORs, thereby specifying toll origination. In the nighttime, a relay NS (not shown in the figure) is released to make a direct connection between the telephone set SUB and trunk CBWT, but the toll origination can be specified even in this state as well as that when a daytime relay NS is in operation. |
