24 Description TB9400 Installation and Operation Manual© Tait Limited March 20171.7.1 Signal PathsFigure 1.6 gives an overview of signal paths within the reciter.Digital P25 signals from the receive RF interface pass through the digitalreceiver and P25 modem to the control software in the RISC processor. Thecontrol software passes the signal through the Ethernet interface to the sitecontroller (P25 trunked networks), to the console gateway (conventionalnetworks), or for a satellite, to the central voter in a simulcast system.Input to the Ethernet interface can be from the site controller (P25 trunkednetworks), from the console gateway (conventional networks), or from thecentral voter in a simulcast system. These inputs are processed by the RISCand passed through the P25 modem to the transmitter. If the base station isitself a central voter, this input can also be a received signal, which is votedon and sent back through the Ethernet interface to the site controller.1.7.2 Online and Offline ModesThe base station normally operates in Online mode, but you can put it intoOffline mode via its web interface.Online Mode In Online mode, the base station performs its normal functions.Offline Mode Some procedures, such as activating firmware or running certain diagnostictests, require the base station to be in Offline mode. This takes the basestation out of service. However, the front panel is still operational and canbe used in the normal way.Figure 1.6 Reciter signal pathsModulatorDemodulator P25ModemFMBasebandAudioG.711ControlADC DDCDACRTPUDPIPTransmitRF InterfaceReceiveRF InterfaceEthernetInterfaceProtocolStackReciter Control BoardCartesianLoopADCTransmitRF Interface(feedbackfrom PA)
