Includes unique AoIP devices such as VENUS 3 audiocodec and Netbox 4 MH interface

TSF is a Portuguese radio station that produces a newscast every half an hour. It counts on a great network of international correspondents. The coverage area of TSF FM includes the North and Center of Portugal, but its programs are also broadcasted through a series of local stations in the South, thus practically reaching national coverage.

Recent popularization of AoIP (audio over IP) distribution systems opens new paths for technical intercom and audio distribution for broadcasters: it reduces required wiring and make operation simpler, but even in that case, it is not a good idea to completely renounce to the advantages of former TDM bus-based systems.

This station has very specific technical requirements, due to the mainly informative nature of its contents. So when TSF’s new Program Production Center engineering planning was started, a system combining both technologies was proposed not having to surrender the advantages of any of these: an intercom system serving Editorial Office and News Production has been built on Dante-based AoIP network, and this is linked to a redundant TDM bus-based matrix combining and organizing the production studios and radio broadcasting circuits.

Also, a VoIP-based broadcasting telephony system has been integrated, featuring two SYSTEL IP 12 devices, which provides agile and economical communications and the stations on-air calls. Further a number of VENUS 3 AoIP audiocodecs for outside broadcasting purposes have also been integrated.


Next picture represents the station’s block diagram.


  • Central Control or DATA CENTER is represented in the centre of this schematics.
  • The Main Auto-control Studios, STUDIO 1 and STUDIO 2 are depicted at the top. Each one counts with its own ARENA digital mixing console.
  • Top right you can see the Transmission Control including the satellite contribution and broadcast system. 
  • Controls 1, 2, 3 and 4 are shown at the bottom of the diagram and each one of the controls has a CAPITOL IP digital console installed. Control 1 and 2 can take individual or combined control of STUDIO 3 and Control 3 and 4 are configured the same way for STUDIO 4. 
  • 5 recording, editing and voice over cabins are represented at the left. These are called “QUIET ROOMS” 
  • Finally, three news room desks are represented at the right, where general news, sports and live programs are elaborated.

Among the central control and the different technical rooms, we can see the following wiring:

  • Ethernet AoIP wiring for (usually stereo) program, represented in red.
  • Ethernet AoIP wiring using for mono intercom, depicted in yellow.
  • AES/EBU backup wiring for (usually stereo) program circuits, in blue.

And the analog backup wiring for the programs (that are usually stereo) among studios 3 and 4 and their associated controls is drawn green.


Both ON AIR studios are equipped with 15 fader ARENA consoles. The audio engine frames are located in the Technical Center and are connected to the matrix using 64 AoIP channels with AES/EBU backup.

To send microphone audio and receive the returns to each headphone, two new Netbox 4 MH AoIP interfaces have been installed in each of these studios.

All three control PCs have AoIP input/output capability and are backed up in AES/EBU for security. Studio 2 has a Behringer auxiliary digital console installed.



There are four production control rooms equipped with an AEQ CAPITOL console. The audio engines are located in the Technical Center. Each core is linking 16 channels with the matrix through the AoIP Network.

Both Controls are sharing Studio. In order to send microphone audios and receive the returns for each headphone at each studio, a Netbox 4 MH AoIP interface is used. Each control room PC is equipped with AoIP input/output.


There are 5 recording, editing and voice-over cabins, known as “QUIET ROOMs”. A PC with AoIP capability is installed in each one of these cabins together with a NETBOX 4 MH AoIP interface to connect the required microphones, headphones and a signaling terminal.


Program and return channels are backed up using AES/EBU links in the Central Control and also through a Netbox 8 AoIP Terminal. Also in this area, the emergency playout system can be found. It would be used in the unlikely event that all duplicate signals from Central Control fails.


The intercom system is installed on virtually all the technical rooms: controls, studios, technical center, booths and also on the editorial rooms. That’s why it required a dedicated installation.

This system includes 64 AoIP channels. It also has inputs and outputs in analogue and other formats. The signaling protocol used and the ability to easily create flexible summing and/or distributing audio routes, allows the system to be used as a complementary infrastructure for audio transport. This acquires special relevance when recording news chronicles, interviews and outside broadcasts.


AoIP technology has made possible the integration of all devices and systems within TSF Technical Center. Such systems are still usually distributed among the different studios and technical rooms in other large radio stations. In particular, the six engine frames of the audio consoles for the studios and control rooms can be found there.

The technical center during the installation process

As usual, all the communications, audio processing and management elements as well as the transmission, reception and monitoring devices have been installed there, including the Systel broadcast telephony system and Venus 3 IP audiocodecs (the only ones in the market featuring Dante AoIP local audio connectivity).

This centralized installation has provided great savings in radial wiring, as all the devices are located in the same place. These systems have been wired to a new audio switching and distribution system that allows any connected signal to reach any destination easily using control interfaces that may be located in the Technical Center, the Studios or even in a remote, Internet-connected location. This way, maintenance tasks are also reduced as they can be remotely managed without the technicians needing to travel to the Program Production Center.

The main elements in this new Technical Center are two AoIP-connected matrixes: CrossNet intercom matrix, and AEQ BC-2000C TDM-bus based matrix for audio switching and distribution with AoIP interfaces, as well as AEQ NETBOX 32 audio interface devices.

Also in this Technical Center, AEQ ARENA and CAPITOL IP audio engines can be found, both of them featuring AoIP Network connectivity.

These systems are related to a variety of devices outside the Technical Center: Arena and Capitol control surfaces, the DANTETM interfaces included in the emission and production PCs, specific audio interfaces Netbox 4MH, Netbox 8 and Netbox 32, as well as user intercom panels.

Structured cabling, Ethernet switches and other Gigabit, QoS-managed IP network elements are connected between these elements.

This architecture has allowed for the installation of only the minimal required devices for audio signal input and control within the control rooms and studios. It has also reduced wiring among the studios and Technical Center, which is implemented using only generic Ethernet cables for the whole installation. Wiring has become flexible and circuit reassignment is extremely easy, providing great savings during both the deployment and operation phases.


The main and novel aspect of TSF Radio Journal is the implementation of a mixed topology where an AoIP network is unified, made more flexible and rendered processing capabilities whereas all the audio signals are routed through TDM-bus based matrixes for both audio and intercom.

The introduction of an intercom matrix used not only for coordination but also for audio routing has been very relevant, too.

The installation tasks were successfully accomplished towards the end of 2016. Workload and responsibility was shared between TSF and AEQ. The Center has been fully functional since then.