page_title: 1 Main Circuit
hierarchical_section_title: 1 Main Circuit
caption_attribution_description: English: NORFOLK (Dec. 22, 2009) Rear Adm. Michelle Howard, commander of Expeditionary Strike Group Two, commends the crew of the multi-purpose amphibious assault ship USS Wasp (LHD 1) during ship's return to Norfolk after a three-month deployment in the Southern Command area of responsibility supporting Southern Partnership Station-Amphib. (U.S. Navy photo by Mass Communication Specialist 1st Class Andrew McCord/Released)
context_page_description: 1 Main Circuit is the term for the shipboard public address circuits on United States Navy and United States Coast Guard vessels. This provides a means of transmitting general information and orders to all internal ship spaces and topside areas, and is loud enough that all embarked personnel are able to hear it. It is used to put out general information to the ship’s crew on a regular basis each day. The system consists of an amplifier-oscillator group which is located in the IC/gyro room, a microphone control station, portable microphones at each control station and loudspeakers located throughout the ship. Control stations for the 1MC announcing system are located at the pilot house, OOD stations on the quarterdecks, aft steering and Damage Control Central area.
  During an incident involving a casualty, the 1MC is a communication tool used by DCA to keep ship members alerted and informed of casualty location area, status, and incident response efforts by the DC organization.
  The 1MC is divided into smaller sub-circuits, such as officer's quarters and topside. At the option of the officer of the deck, some details are not passed on certain circuits.
context_section_description: 1 Main Circuit (1MC) is the term for the shipboard public address circuits on United States Navy and United States Coast Guard vessels. This provides a means of transmitting general information and orders to all internal ship spaces and topside areas, and is loud enough that all embarked personnel are able to (normally) hear it. It is used to put out general information to the ship’s crew on a regular basis each day.  The system consists of an amplifier-oscillator group which is located in the IC/gyro room, a microphone control station, portable microphones at each control station and loudspeakers located throughout the ship.  Control stations for the 1MC announcing system are located at the pilot house, OOD stations on the quarterdecks, aft steering and Damage Control Central area.
  During an incident involving a casualty, the 1MC is a communication tool used by DCA (damage control assistant) to keep ship members alerted and informed of casualty location area, status, and incident response efforts by the DC organization.
  The 1MC is divided into smaller sub-circuits, such as officer's quarters and topside.  At the option of the officer of the deck, some details are not passed on certain circuits.
  The 1MC is also used for transmitting various alarm sounds to alert the crew of specific impending dangers such as an inbound anti-ship missile, chemical attack,  collision, or a flight deck crash.
caption: Then-Rear Admiral (lower half) Michelle J. Howard addresses the crew of USS Wasp (LHD-1).
exif: {"Image ImageDescription": "091222-N-2564M-106\nNORFOLK, Va. (Dec. 22, 2009) \u00f1 Commander, Expeditionary Strike Group Two, Rear Adm. Michelle Howard commends the crew of the multi-purpose amphibious assault ship USS Wasp (LHD 1) after it pulled into its homeport of Norfolk, Va. following a nearly three-month deployment the Southern Command in support of Southern Partnership Station-Amphib. (U.S. Navy photo by Mass Communication Specialist 1st Class Andrew McCord/Released)", "Image Make": "NIKON CORPORATION", "Image Model": "NIKON D300", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS3 Macintosh", "Image DateTime": "2009:12:23 11:38:20", "Image Artist": "", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "816", "GPS GPSVersionID": "[2, 2, 0, 0]", "Image GPSInfo": "1472", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1586", "Thumbnail JPEGInterchangeFormatLength": "5533", "EXIF ExposureTime": "1/400", "EXIF FNumber": "14/5", "EXIF ExposureProgram": "Shutter Priority", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2009:12:22 11:02:36", "EXIF DateTimeDigitized": "2009:12:22 11:02:36", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Spot", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "62", "EXIF SubSecTime": "25", "EXIF SubSecTimeOriginal": "25", "EXIF SubSecTimeDigitized": "25", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "4288", "EXIF ExifImageLength": "2848", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "1440", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CVAPattern": "[0, 2, 0, 2, 0, 1, 1, 2]", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "93", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0"}