From: owner-ais_wg@radioaid.rdc.uscg.gov on behalf of David
Pietraszewski [dski@radioaid.rdc.uscg.gov]
Sent: woensdag 7 maart 2007 23:26
To: Class B AIS WG
Subject: [Fwd: AIS Class B Message 24 Part B 42-bit Vendor ID field]

As requested by Joe...

-------- Original Message --------
Subject: AIS Class B Message 24 Part B 42-bit Vendor ID field
Date: Wed, 7 Mar 2007 15:08:18 -0500
From: "Hersey, Joe" <Joe.Hersey@uscg.mil>
To: "Luft, Lee " <Lee.A.Luft@uscg.mil>
CC: "DPski" <dski@radioaid.rdc.uscg.gov>

Lee, would you please send this out over ais_wg@radioaid.rdc.uscg.gov for me?  Our email domain changes prevent me from sending it.  Thanks.


One of the last things pending Class B AIS approval in the US is what to do about Message 24 Part B 42-bit Vendor ID field. 
There's an argument to be made that using that field is worth the trouble for reasons of security.  We are considering proposing the following for US Class B AIS certification, and wanted to get your feedback.

"We propose that the Message 24 Part B 42-bit Vendor ID field include the manufacturers' identity, unit model, and unit serial number.  The manufacturer's identity should consist of a three-character (18 bit) ASCII symbol as described in ITU-R Recommendation M.1371 (series), based upon NMEA 0183 (version
3.01) Appendix III, available from the National Marine Electronics Association, Seven Riggs Avenue, Severna Park, MD 21146, http://www.nmea.org.  We understand NMEA will assign a manufacturer's identity at no charge.  The coding of the remaining 24 bits, containing unit model and serial number, should be left to the manufacturer.  The manufacturer should include coding information in its certification documentation, or if proprietary, be provided to the Commission and Coast Guard."

For non-US folks: IEC 61162 section 5.5.3 references these same manufacturer's identities as "manufacturer mnemonic codes".

Regards,
JoeHersey