MOST Protocol Gaining Ground

MOST is headed this way.

The Media Oriented Systems Transport networking protocol, which has worked its way into mostly high-end European cars over the last five years, is gaining traction in Asia and eventually could see wider use in North America, a key supplier says.

Designed to allow onboard infotainment systems to talk to each other, while reducing wiring needed to connect devices such as DVD players and radios, the MOST operating standard is in place on 38 vehicle platforms (soon to be 40), say officials from Hauppauge, NY-based SMSC.

MOST was developed by a consortium of companies, beginning in 1998 with OASIS (since purchased by SMSC), DaimlerChrysler AG, BMW AG, Audi AG and Harman/Becker Automotive Systems GmbH. It since has expanded to include 16 auto makers and more than 70 suppliers.

Its first application was in the BMW 7-Series in 2001, but the migration into mid-range vehicles is growing, and the list of vehicles now employing the protocol includes some low-end models such as DC's Smart and Mitsubishi Motors Corp.'s Colt. Other vehicles with MOST networks include Mercedes A-, C-, E- and S-Class cars and the Porsche Boxster and 911.

In using MOST in one platform, DC reduced the number of cables from six to four, cut cable length by 25% to 29.5 ft. (9 m) and eliminated two of every three conductors per cable, SMSC says.

Likewise, cable costs were slashed more than half. Initially, the MOST standard was designed to work with plastic optical fiber, in part to eliminate electromagnetic interference (EMI) issues, but also because of its lighter weight and ease of recycling.

But using plastic optical fiber requires wiring harnesses to be assembled differently, and that may have caused some auto makers to shy away from the technology.

However, earlier this year, under the direction of Toyota Motor Corp., the MOST consortium developed a way to substitute inexpensive and easy-to-handle unshielded copper wire in place of optical fiber, allowing OEMs to employ MOST while maintaining existing production methodologies.