User's Manual

Doc. No.
Rev.
Date
DRAFT
1.01
2012-01-27
Damm Cellular Systems A/S, Denmark
TetraFlex
®
7.5 Manual - BS41x
TetraFlex® 7.5 Manual 1-30
1.3.7.2 External alarm connections
The BS is provided with 8 external alarm inputs. One of these is reserved for the “Door Open”
alarm (Not yet implemented) and the rest are currently not pre-defined for a specific function.
All alarm inputs are provided with a 1Kohm resistor to +5V. To activate an alarm the input
shall be grounded.
The BS is also provided with 3 alarm outputs currently not allocated any specific function.
The outputs are open collector outputs capable of sinking 0.25A. The outputs are protected
for inductive transients with 36V zener diodes.
The alarm connections are provided with LSA-type connections, accepting solid wires with
the dimension 0.4mm
2
to 0.6 mm
2
.
1.3.8 Back-up battery for BS41x
1.3.8.1 Introduction
This application note describes how to attach a backup battery to the BS41x Tetra Base
Stations.
All the BS41x versions are powered with one or several PS411 Power Supplies.
The PS411 can be powered directly from an external DC source of –48V.
The PS411 can also be powered directly from AC mains of 100 to 240V, 47-63Hz without any
battery backup. This mode is convenient at test of the Base Station.
The standard installations, however, is the combination of AC mains power feed with a –48V
lead-acid backup battery connected. The PS411 has all the build-in features to have the
battery connected and charge it. This allows uninterrupted service for a period depending on
the size of the battery. For very service-critical systems this can be extended with a Diesel
generator starting automatically after a certain period of battery operation.
All BS versions can be connected to an external –48V lead-acid battery. The external battery
kit includes a circuit breaker to protect the battery and the TS411 temperature sensor to allow
the PS411 to provide a temperature compensated charging voltage.
1.3.8.2 Selecting external batteries
Several issues should be taken into account, when selecting batteries. In general, only
battery types intended for use as back-up battery in telecom systems should be used.