| 摘要 |
PURPOSE:To attain an additional dial from a DP telephone set by providing a means receiving a dial code from the DP telephone set, converting the code into a voice frequency signal of the PB dial system and transmitting the converted result to the private branch of an automatic exchange at an incoming side to the private branch of the automatic exchange. CONSTITUTION:An outgoing register 24 transmits a PBX dial tone to an outgoing DPTEL112 when the dial code transmitted from the DP telephone set 112 is discriminated and the destination of incoming is a PBX40 having the capacity for an extension by direct dial connection. Further, the DPTEL112 transmits the extension number by an additional dial of the PBX transmission system. A central controller 25 makes an additional number storage circuit 272 store the extension number. A PB sender 26 is connected to the trunk line trunk 23, reads a station subscriber number from a station subscriber number storage circuit 271 and transmits it via the trunk line trunk 23 and a public station line 30. A PB register 41 of the incoming side PBX40 receiving the incoming call is connected by a link D, a PBX dial tone is transmitted to the trunk line trunk 23, the PB sender receiving the tone transmits an additional number (extension number) to the trunk line 30 so as to allow a telephone set 30 to be connected without the operator. |
