Overview
ISO 21806-8:2020 specifies the 150‑Mbit/s optical physical layer (MOST150 oPHY) for Media Oriented Systems Transport (MOST), a synchronous time‑division‑multiplexing network used in road vehicles. The standard defines applicable constraints, interfaces and parameter values to guide development of MOST150 optical hardware and measurement methods. Typical product types covered include fibre optical links and connectors, fibre optic receivers and transmitters, electrical‑to‑optical (E/O) and optical‑to‑electrical (O/E) converters, and packaged fibre‑optic transceivers.
Keywords: ISO 21806-8:2020, MOST150 oPHY, 150-Mbit/s optical physical layer, Media Oriented Systems Transport, automotive optical transceiver, fibre optic automotive.
Key topics and technical requirements
ISO 21806-8:2020 addresses the physical‑layer characteristics and conformance requirements needed to build interoperable MOST150 optical links. Major technical topics include:
- Physical layer service interface to the OSI data link layer (data types, event indications, action requests).
- Basic physical layer requirements: logic signal types (single‑ended low‑voltage digital, differential LVDS), specification points, and phase‑variation constraints.
- Clock, phase and timing: wander, jitter, clock recovery and reference clock considerations for synchronous TDM operation.
- Link quality and network quality parameters and measurement points (SP1–SP4) for optical links.
- Measurement models & methods: golden PLL, jitter filter, retimed bypass mode, stress patterns, and optical signal level detection regions.
- Power sequencing and monitoring: frequency reference, power‑on/power‑off sequences, power supply monitoring.
- Electrical interfaces and packaging: LVDS interfaces, bit‑rate tolerance, SMD and through‑hole FOT packages, connector interfaces and losses.
- Device connectors and transceiver pinouts: defined package types and signal definitions for OEC/EOC devices.
These elements provide manufacturers and test labs with the parameters and measurement techniques required to ensure interoperability and reliable performance of MOST150 optical implementations.
Practical applications and who uses this standard
ISO 21806-8:2020 is intended for:
- Automotive system architects and OEMs designing MOST‑based infotainment and in‑vehicle networks.
- Component manufacturers producing fibre optic transmitters, receivers, E/O and O/E converters, and transceiver modules.
- Connector and cable suppliers specifying automotive fibre links and connector loss budgets.
- Test houses and validation engineers developing conformance tests, jitter/wander measurements, and link qualification methods.
- System integrators ensuring MOST150 network quality and power sequencing compliance.
Adopting this standard ensures consistent optical physical‑layer behavior, simplifies component interoperability, and reduces integration risk in automotive multimedia and data networks.
Related standards
ISO 21806-8 is Part 8 of the ISO 21806 series for MOST. Implementers should consult other parts of the ISO 21806 series and relevant automotive electrical/optical interface standards for complete system design and compliance.