Pro Intercom MS300 Master Station

For those who do not require all the capabilities of the MS301, Pro Intercom offers the MS300. It has all the features and qualities of the MS301, without the IFB, Paging and Auxiliary Audio functions, resulting in considerable cost savings.

Each circuit has a characteristic impedance of 200 ohms at audio frequencies, allowing many beltpacks to be connected together without significantly changing the circuit performance. The termination networks are automatically removed and inserted during circuit linking to ensure a constant impedance for all circuits. The termination networks may also be manually removed by setting a switch on the rear panel, if desired. This may be useful when using an adjunct network, or if interfacing with a larger communications system.

The internal power supply provides power for up to 66 beltpacks connected to the circuits. Power is well regulated at 24 volts DC and will automatically adjust down during periods of line voltage brownout or high loading with loudspeakers stations or other equipment. Each of the 3 circuits has its own rectifier, regulator and protective components, so a fault in one circuit does not affect the others. Short circuit protection and current limiting prevent component damage in the event of mis-connection or cable failure. The toroidal transformer, coupled with linear regulators ensure noise-free operation under all conditions. The MS300 has a quiet built-in fan that turns on automatically when needed to cool the unit. Front panel indicators show the status of all circuits and allow an operator to quickly address a circuit problem.