APPLICATION NOTE

DISCUSSION SYSTEM WITH UP TO 150 MICROPHONES

This application note details how to extend the Philips CCS 800 Discussion System.

• Allows use of CCS 800 System for larger meetings.
• Up to 150 microphone units possible.
• Uses 1 or 2 extra CPSUs (Central Power Supply Units).
• Each CPSU powers up to 2 x 25 microphone units.
• System cabling made-to-measure by installer.
• Cable length ≤ 100 M (328 FT) per group of 25 microphones.

COST-EFFECTIVE SYSTEM EXTENSION

Meeting the need to use the CCS 800 Discussion System in larger meeting and conference situations, a cost-effective solution is now available to extend the system up to a maximum of 150 microphones. This solution is based on the use of 1 or 2 additional CPSUs (Central Power Supply Units) connected to the system's original or master CPSU. System control and I/O functions continue to be handled by the master CPSU. The extra (power slave) CPSUs act as precisely regulated power supplies for the additional microphone units.

Each CPSU powers up to 50 CCS 800 microphone units, connected in two 'daisy chains' of 25 units each. An external equalizer unit can be connected to compensate for room acoustics by equalizing the audio signals between microphones and loudspeakers. The CPSU interconnection cable assembly is prepared locally by the installer using made-to-measure cabling.

MADE-TO-MEASURE SYSTEM CABLING

Connection of 1 or 2 extra CPSUs for up to 100 or up to 150 microphone units, respectively, is according to the block and cabling diagram. As the diagram shows, the master CPSU handles the control, mode selection and I/O functions. Only the power and ground connections of the extra 1 or 2 CPSUs are used. It is advisable to install the extra CPSUs out of sight because the control and I/O functions of these units are not used. The CPSU operator should be instructed that the control and I/O functions of the extra CPSU units are not available.

Covering the needs of larger installations, total cable lengths may be up to 100 m (328 ft.) for each 'chain' of 25 microphones. It is recommended that only the shielded CCS 800 system cable LBB 3316 is used for correct performance and noise immunity.

BLOCK AND CABLING DIAGRAM FOR EXTENDED CCS 800 DISCUSSION SYSTEM

A diagram illustrates the configuration with a master CPSU and two power slave CPSUs, each supporting two chains of 25 microphones. Minor changes in audio signal and signal-to-noise levels may occur with a maximum CCS 800 system configuration (more than 50 microphones), but these changes will have no significant effect on perceived system performance under normal operational conditions.

To ensure stable test mode operation, the maximum ambient temperature must not exceed 35°C (93°F) when using a maximum system configuration.