Overview
ISO 21792:2019 - Ships and marine technology: Guidelines for onboard telephone equipment - gives practical recommendations for the design, installation, performance testing and maintenance of shipboard telephone systems. The standard covers automatic telephones, common battery telephones (DC 24 V), battery-less telephones and sound‑powered telephones, and specifies shop tests, onsite tests, and maintenance tests to verify functionality and reliability. It does not apply to digital, LAN/VoIP or wireless telephones (these were excluded while under development).
Key Topics
- Scope and terminology
- Definitions for telephone types (automatic, common battery, battery-less, sound‑powered) and equipment such as automatic telephone exchangers.
- Quality of communication
- Recommendations to ensure intelligible voice transmission and connectivity across shipboard telephones.
- Measures to prevent howling (audio feedback) and to suppress ambient and narrowband noise.
- Data and signal requirements
- Signal condition, input/output considerations and connection guidance for automatic and analog telephones.
- Installation requirements
- Environmental considerations (temperature, vibration, swinging motion), dust/water protection, explosion protection and cabling best practices for shipboard environments.
- Performance testing
- Shop tests for factory verification and onsite tests for installation acceptance (automatic and non-powered telephone types).
- Maintenance
- Routine and periodic maintenance procedures, corrosion mitigation, periodic maintenance programmes and recommended replacement periods.
Applications
ISO 21792:2019 is directly applicable to the selection, installation and upkeep of onboard telephone equipment in merchant vessels, offshore units and other marine platforms. Typical uses include:
- Designing ship communication systems and specifying shipboard telephones for newbuilds and refits.
- Preparing factory acceptance and onboard commissioning test plans (shop and onsite tests).
- Developing maintenance schedules and spare/replacement policies for telephony hardware.
- Guiding manufacturers on performance and environmental requirements for maritime telephone products.
Target users: shipbuilders, marine equipment manufacturers, ship owners/operators, classification societies, marine engineers and shipboard technicians.
Related standards and references
- Prepared by ISO/TC 8 (Ships and marine technology), Subcommittee SC 6 (Navigation and ship operations).
- For terminologies and electrotechnical definitions consult IEC Electropedia and the ISO Online Browsing Platform.
- Note: ISO 21792:2019 complements other international shipboard communications and electrical installation guidance; consult relevant IMO, IEC and national maritime regulations when applying this standard.
Keywords: ISO 21792:2019, onboard telephone equipment, shipboard telephones, automatic telephones, sound-powered telephones, common battery telephone, battery-less telephone, performance tests, maritime communication systems.
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