Characteristics

Professional Quality

NEXUS STAR is built for professional use. Beside exceptional audio quality, the developers were committed to outstandingly high reliability. This is especially true, for external impacts such as power failure or broken optical cables.

Audio Quality

The consistent use of first-class analogue components throughout the entire NEXUS network ensures the highest sonic fidelity in recording, mix-down, and sound-reinforcement applications. The A/D and D/A converters feature a dynamic range of 133 dB(A), and the microphone A/D converter has greater than 150 dB.
NEXUS STAR meets all requirements imposed by functional specifications 3/2 and 3/5 (as defined by the German Institute for Radio Broadcasting Technology, IRT), also for analogue inputs and outputs. Digital and analogue components have successfully been tested by the Institute for Radio Broadcasting Service Technology (RBT) in Nuremberg/Germany, the Italian Radio Broadcasting Service, and the Swiss Radio Broadcasting Service.

Fibre-optic Networking

NEXUS system wiring requirements are reduced to a minimum. NEXUS STAR and NEXUS Base Devices are interconnected solely via duplex fibre-optic cables for audio-signal, word-clock and control-data distribution. This simplifies the installation of widely distributed systems and prevents problems in mobile use.

Distributed Control

Thanks to its own dedicated controller board, the basic functions of a NEXUS STAR are provided independently of control computers and fibre-optic connections. Thus, the failure of one or more control computers does not affect the audio transmission on the routing system.
The NEXUS data exchange system uses all connections available on the Base Device network. Therefore, it remains operational even if fibre-optic lines or Base Devices break down; thus, the audio network and any emerging partial networks remain largely operable on their own.

Data Retention

The RAM on the RCX and XCPU controller boards is battery-backed; in case of power failure, the most recent Base Device status is memorized. When power is up again, it will take only seconds to restore all settings – NEXUS STAR will be ready for operation in no time.
System and routing settings are also retained: When the overall NEXUS system is powered up, it resumes its most recent status within a few moments. All this is achieved automatically on the NEXUS system independently of any control computers.

Self-monitoring Functionality

NEXUS STAR and the NEXUS network continuously monitor their own functionality and the network status. Problems detected by the system include:

• Failed or wrongly installed boards
• Breakdown of optical lines
• Power-supply failure
• Sync-source failure
• Base Device failure on the network
• Exhausted routing capacity of Base Devices or connections

Failed or wrongly installed module boards will normally not affect other functions or module boards. The boards can be replaced even while the system is in use.

Failure Indicators

Error messages are distributed system-wide and are displayed on all active control computers. Furthermore, the graphical control software logs error messages to simplify subsequent analysis.
In the system view, the graphical control software indicates failed boards, power supplies, and Base Devices by red-coloured icons, thus providing a quick survey of the system status. In addition, the dedicated Power Check window provides detailed information on the supply voltages of the Base Devices.

Redundancy of Fibre-Optic Lines

In many NEXUS installations, wiring from the NEXUS Base Devices to NEXUS STAR is doubled up to provide for a redundant path. With redundant connections like these, NEXUS transmits every signal from the Base Device over the two parallel lines to NEXUS STAR. NEXUS STAR then decides which of the two input signals to use. Both signals are constantly monitored for data errors using CRC (cyclic redundancy check). NEXUS will normally ignore the redundant signal; however, if an error occurs on the »live« signal while the secondary signal received in parallel is still »good«, NEXUS will automatically switch to the other port within a single sample.
The result is an smooth inaudible change to the good signal. This is true redundancy! Of course, the same is true for the return path to the Base Device.

Maintenance and Service

Maintenance of the NEXUS audio network and the NEXUS STAR router is hardly an issue. »Analogue« boards do not need to be calibrated – there are not even any trim potentiometers! Servicing is limited to the replacement of the RCX´s and XCPU’s buffer battery that must be performed when the system reports that the battery is exhausted (which should only occur at around five year intervals).

For cases of servicing, the system provides numerous support options:

• A control computer such as a notebook PC can be connected to the NEXUS network for error analysis.
• The graphical system view of the control software shows the physical location of failed boards.
• All module boards and their ports are accessible from the front, so they can easily be checked.
• All boards (except the RCX) can be installed and/or removed during operation without affecting any signal (hot-swap capability).
• Newly replaced module boards are detected and updated within seconds.
• The firmware of all Base Devices on the NEXUS network can be updated from a single control computer.
• A remote-maintenance system is available on request. This system provides for quick and low-cost support by the manufacturer over ISDN, analogue phone lines, or the Internet.
• All events are logged in the control computer.