User's Manual

Hot Standby Operation
RFI-148 & RFI-900 High Output Power Paging Transmitters User Manual Page 47 of 134
7. Hot Standby Operation
7.1 Overview
Hot standby operation allows the transmitter to operate in sites with high uptime requirements. It features
automatic fail-over to a secondary transmitter. Hot standby operation is an optional variant to the RFI-148 and
RFI-900 that requires an expansion port internal to the RFI-148 or RFI-900, and an additional external control
unit (“RFI-PHSB”: Paging transmitting Hot-Standby Box). The installation of such a system is illustrated in
Figure 18.
RFI-148 250
(Primary)
RFI-148 250
(Secondary)
RFI-PHSB
Base Station Controller
(Secondary)
Base Station Controller
(Primary)
RF out
Expansion port
Expansion port
RF out
RF out
LIU
LIU
Figure 18: Hot standby system
The RFI-PHSB contains a high power RF switch to ensure minimal signal loss from the active RFI-148 250
to the antenna. The RFI-148 250 transmitters connect with digital signals to the RFI-PHSB using DA15
connectors.
The pair of RFI-148 250 transmitters assume either a Primary or Secondary role. The role of the transmitter is
determined by which port it is connected to the RFI-PHSB, there are two ports “Primary” and “Secondary”.
The typical behaviour is that the Primary RFI-148 250 is keying up and sending paging data.
Encoder Interface -> Hot Standby