RACAL CABIN UNIT 77252 AC ENGLAND SR P0359 RACAL MARINE CONTROL 13:19

This unit serves as a remote station or “slave unit” within a larger integrated marine intercom system (likely part of the Racal “Shipboard Electronic Office” or similar). Its primary purpose is to provide reliable, hands-free voice communication and to broadcast general alarm signals to key areas of a vessel, such as cabins, mess rooms, and officer quarters.

Key Features and Capabilities

1. Loudspeaker/Microphone Unit: The core of the device is a combined loudspeaker and microphone, allowing for hands-free operation. When a call is received, the audio is broadcast through the loudspeaker. To respond, the user simply speaks, and the built-in microphone picks up their voice without needing to lift a handset.

2. Call Indicator: The unit features a prominent visual indicator (a light) that illuminates when a call is incoming. This is essential in noisy engine rooms or for personnel who may be resting in their cabins.

3. “Press-to-Listen” Switch: A key feature is the “CALL CANCEL / PRESS-TO-LISTEN” switch. In its normal position, the unit is on standby, listening for the microphone. Pressing this switch silences the call indicator and forces the audio to the loudspeaker, improving intelligibility in very noisy environments. Holding it down can also be used to reset a call alarm.

4. General Alarm Relay: This is a critical safety function. The unit contains a relay that, when activated by the ship’s central alarm system, will broadcast the General Alarm signal (typically a continuous or intermittent siren/tone) through its loudspeaker. This ensures alarms are heard in all equipped spaces.

5. Rugged Marine Design: Built to withstand the harsh conditions at sea, including:

   • Resistance to salt spray, humidity, and temperature variations.

   • Robust construction to handle vibration and shock.

   • Compliance with relevant marine standards (e.g., Lloyds, DNV).

Typical Use Cases

• Cabin Calling: Allowing the bridge or engineer control room to make announcements or directly call specific cabins.

• General Alarm Sounder: Acting as a local node for the ship’s emergency alarm system.

• Mess Room / Recreation Room: For making general announcements to crew in common areas.

• Engine Room Satellite Station: Providing communication links to isolated control points within the machinery space.

Technical Context

• Manufacturer: Racal Marine Limited, a highly respected British electronics company, now part of the Thales Group.

• System Integration: The 77252 is not a standalone device. It must be connected to a Racal Master Station or Central Control Unit (e.g., models like the Racal 77075 or 77076). The master station provides the power, switching logic, and control to manage the network of cabin units.

• Power Supply (AC): As indicated by “AC,” it is designed to be powered by the ship’s alternating current supply, typically 115VAC or 230VAC, which is converted and regulated within the master station or a separate power unit.