The MSM301 attaches to an MS301 to double the number of available independent circuits from 3 to 6. The new circuits: D, E & F have all the capabilities of the original 3, including program audio insertion and control and the ability to use each circuit as either intercom or IFB with program muting or ducking. Connection of the two units is via D-Sub connector and the short cable is supplied with the MSM301. As with the original 3 circuits, each of the new circuits has 2 XLRs on the rear for connecting stations. The number of stations con- nected any of these XLRs can be further increased by the use of an SB1 accessory.
The MSM301 is powered by the MS301 to which it is attached. It does not increase the amount of current available and is intended only to increase the number of independent communications circuits. The total current available remains at 2.4A, roughly the equivalent of 75 beltpacks. If your objective is only to connect more stations to the three circuits on the MS301, the MSM301 is not necessary. You can accomplish this with SB1s, Y-cables and the loop-through function on most stations.
Circuits may be linked when required, as may be the case in sound or lighting checks and rehearsals. You may link D to E or select ALL. If ALL is selected on both the MS301 and MSM301 all 6 circuits will be linked.
The Status Bar of LEDs indicates that the unit is receiving its 24 volt operating current from the MS301 (green), and the trouble status of any of the circuits (red). If there is a problem ona circuit the red LED will flash. If the problem is serious enough to damage the MS301 pow- er supply components the red LED will be constantly ON and the circuit disconnected until repaired. Most probable are short circuits between Pin 2 and ground or Pin 1-3 reversals in the system wiring. Phase must be maintained when using microphone cable for intercom.
On the rear panel there are DIP switches to allow you to choose between ducking and mut- ing the program audio in the IFB mode, and for lifting the termination circuit of each circuit individually. The MSM301 automatically maintains the 200W termination impedance when linking, but there may be applications where one of its circuits is connected differently.
The MSM301 is intended to be located next to the MS301 and not remotely. For remote Master Station functions, see the RSM300 (Remote Sub-Master 300). Attempting to use the MSM301 other than as an extension of the MS301 will almost certainly damage the unit as it is integrated with the microprocessor in the MS301.