End-of-line devices are employed to ensure that the audio signal is transmitted without interference from the amplifier outputs of the system to the final speaker in the line. In the case of safety-critical installations, such as voice alarm systems, a reliable, high-performance line termination resistor is crucial to ensure transmission integrity.

Line monitoring in safety equipment consists of knowing if all the elements present in the communication line are operating correctly, the way they are expected to work.

In the case of public address and voice alarm systems, the functionality of speaker lines can be compromised for the following reasons:

  • Ground derivations from any of the points of the line.
  • Possible cuts in the line (open circuits).
  • Short circuit of some elements in the line itself

 These potential errors can be detected by the amplifiers thanks to the end-of-line modules, justifying their use in this type of project.

For these cases, we has developed the TFL-2 end-of-line module for ONE and NEO systems, which are certified according to the international standard EN-54.

Combining the measurement capabilities of these systems with the TFL-2 allows for a precise measurement of the impedance of the speaker line, enabling monitoring all the way to the last speaker without the need for a return path, even in low-power connection lines.

Furthermore, the TFL-2 also enhances the monitoring of the amplifier, not just the speaker line. Not all available end-of-line modules are equally reliable and do not provide the same level of performance as the TFL-2 to ensure the operational safety of the installation.

Having a TFL-2 in a public address installation implies a series of advantages that make it stand out above other devices present in the market.

 The impedance of the TFL-2, which is tuned to the measurement frequency and switchable in two stages, means that very little energy from the amplifiers is required for the measurement process. Since the impedance curve of the TFL-2 complements, or runs counter to, the impedance curve of a speaker, the TFL-2 can be effectively disregarded in calculating the power balance of the individual amplifier channels. This results in the system requiring much less additional power compared to using a conventional resistor.

The robust casing of the TFL-2 ensures long-term protection against mechanical and electrical influences, helping to avoid issues over the lifetime of the system.

Overall, TFL-2 modules offer excellent value for money as they can prevent a wide range of problems when installed in sound reinforcement and voice evacuation systems.