IP remotely controlled public address system

The public address system has been designed as a replacement of the existing RU-6 public address systems and of other similar equipment during the transition to the remote control system. It includes a high-power low frequency amplifier 300 W 100 V, control circuits for supervision, VoIP circuits for the input of low frequency signal in the digital form. Besides the standard features of the LF amplifier it includes functions needed for remote operation and supervision of the operating conditions.

Controlling public address system

The basic input of the low frequency signal is an Ethernet interface with VoIP Protocol and the option of the simultaneous operation of two independent channels. The first channel is designed for connecting to the centralized announcement system, the second channel for local or remote access using VoIP phone. The other connecting options of the lowfrequency signal are the line input and the microphone input.

The parameter settings

All settings of analogue parameters (volume, heights, basses, levels of individual inputs and their priorities) are carried-out digitally. Detection of the current state, control and configuration are possible by website browser. Current operating states and information from the inner auto-diagnostics can be transmitted into the superior supervisory system by SNMP Protocol and it is possible to record the operation history by SYSLOG Protocol. The internal real time clock can be synchronized using the NTP protocol.

The main advantages of IP  public address system

  • Fully remote- controlled and supervised public address system with power output of up to 300 W for 100 V distribution for the version with 230 V AC power supply and 150 W for the version with 48 V DC power supply.
  • Integrated input VoIP for direct connection to the digital infrastructure
  • 6 output loops with separate indications of currently broadcasted messages
  • Communication and control by standard protocols (HTML, SNMP, NTP, SYSLOG)
  • Option of direct coupling with the automatic announcement system


The basic technical description

The public address system is built-in in the case designed for installation to 19“ rack, height 3U and depth of 40 cm. Its weight is 18 kg.

Front panel

The front panel includes two Ethernet connectors (one for connecting into the system, the second for connecting of the service technician), LEDs indicating the current state of the lines and of the public address system itself, and alphanumeric LCD display

Rear panel

On the rear panel there are EURO plugs for connecting 230 V power supply and connectors for connecting the output lines. Cooling is forced by ventilators, the coolers are located inside the public address system case.

Regular operation

The regular operation is expected to proceed in the automatic announcement system, where compared with the existing equipment the use of an external computer with the sound card is not necessary.

Local or remote announcements via the standard VoIP network

Other options are the local or remote announcements via the standard VoIP network with a variable priority. For these two options the public address system uses two independent VoIP inputs.

Analog inputs

It is also possible to connect the input signal to the line or to the microphone input. Inputs use adjustable priorities.

Automatic switching of the day and night mode

Real time circuit is synchronised by NTP Protocol from the network and it allows as well automatic switching of the day and night mode.

Check of the carried-out announcements

To check the carried-out announcements current flowing through the line is measured in each of the six output lines. Input circuits formed by an output transformer, relay switching the output lines and output current sensor are galvanically separated by 4kV insulation barrier.

Basic technical parameters


Dimensions 19“ module height 3U and depth 40 cm (without connectors), width
(without handles) 43 cm, depth 40 cm, height 9 cm
The Public Address System has been designed for installation into 19“ (rack)
distributor, vents on the front and rear panel must not be covered
Weight 18kg
Cover IP20
Working temperature range 0 až 45 °C
Storage temperature range –20 až 60 °C
Humidity 20 až 80 %, nekondenzující
Rated power supply voltage 230 V ±10 %, 50 Hz, max. 8 A (300W verze),
nebo 48 V stejnosměrných max. 10 A (48V verze)
Output power till 100V of
300 W (verze s napájením 230 V) nebo 150 W (verze s napájením 48 V)
The number of output loops 6
LAN (ethernet) – 2× RJ45
230 V intake EURO plug
48 V intake two pole connector
Output lines 2 two-pin plugs PA256/7,62, cable plugs PA256/7,62 are included in the source supply
Microphone input, line input and output for analogue recording RJ11 plugs

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