MIS-321/E intercommunication system is considered for establishing voice communication between different divisions of a boat (e.g. cabin, engine room, and deck). Using this system, for operating each radio, captain and or co-captain can transmit/receive voice of the radios via the headset on their head instead of the radio handset. Important advantage of the system is getting access to the two individual radios for transmitting status by captain and co-captain simultaneously. Controlling RX and TX of the radios is accomplished via their control panel.MIS-321/E can be connected to wireless intercommunication system so that wireless intercommunication interface is connected to the co-captain port and when the wireless intercommunication system is connected to the system, wireless crews get the co-captain access. In order to control the system parameters, a panel is considered to set the system operation settings. In the MIS-321/E system the DNR technique is used for rejecting background noises so that decreases the noises considerably and causes to increase voice quality of intercommunication. In addition, this system includes an auxiliary input so that can be used for connecting voice systems to propagate music, alarm, and …