Talk:NMEA 0183

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Contents 1 div 2 Protocoll 2.1 Update speed 3 Serial Configuration 4 Important Error in Protocol Spec

[edit] div

Currently, the article doesn't explain how raw GPS satellite data is converted into a stream of NMEA 0183 data and how this stream contains information about where on the world this GPS receiver currently is. I think this would be a great addition to this article, as GPS localization is the most important use of NMEA 0183. --Abdull 09:39, 29 March 2007 (UTC)

The proper place for that discussion is in the GPS article; once the GPS receiver has done it's magic, formatting the results is trivial. NMEA is used for things other than GPS, too, so an "in depth" (pardon the pun) description belongs elsewhere. --Wtshymanski 17:53, 29 March 2007 (UTC)

I agree --Steinmb 04:03, 9 August 2007 (UTC)

[edit] Protocoll

I found this article extremely confusing - and left more unanswered than said.
(a) It specifies a sentence structure, then gives what appears to be an example - but that example has very little semblance to the specified protocol

(b) I know that there are multiple sentences possible - but there is no mention in the article about which sentences equipment emit, and how they emit them. Is there some 2-way communication where a listener can ask for specific sentences? Or does a talker simply emit as many sentences as it knows how, in regular sequence, and it is up to the listener to find and parse whatever sentences it wants? Gary Turner 22:51, 17 April 2007 (UTC)

All devices have diffrent set of sentences it transmitt and are able to receive, impossible to litst them all here :) No it is noe possible to poll the eq. asking for data. Normally you can finetune what sentences that are to be sent and what taker to use (ID) like GPS uses GP, Gyro uses HE, the list is long. --Steinmb 04:03, 9 August 2007 (UTC)

[edit] Update speed

(c) Do things that talk NMEA talk all the time? Is that the default behaviour, or do they need to be addressed somehow to talk? Gary Turner 22:51, 17 April 2007 (UTC)

Normally talk "all the time" but there is exeptions. Echo sounders normally transmitt as soon new data is available, in transmitting with higher update speed on shallow water then on hundreds of meter deep. --Steinmb 04:03, 9 August 2007 (UTC)

(d) Under vendor extensions - where you say "special messages to the standard NMEA" - do you mean "special messages in addition to the standard NMEA" Gary Turner 22:51, 17 April 2007 (UTC)

(e) It would probably help to provide a link to the specific piece of equipment you mention. Gary Turner 22:51, 17 April 2007 (UTC)

The 'Serial configuration' section has nothing to do with the NMEA 0183 protocol. The values stated are merely default settings. --193.163.1.101 10:56, 30 May 2007 (UTC)

[edit] Serial Configuration

The listed serial communications specification is extremely important - it's the actual, OFFICIAL configuration specified in the NMEA 0183 standard v. 2.01). Any other use of the sentence structure at different baud rates, etc. may be "NMEA-like", but it would not be NMEA 0183 strictly speaking. 155.212.113.117 13:34, 16 July 2007 (UTC)

I think we need to add the diff between ver. 1.5 2.0 2.01 AND that different equipment is transmitting with different HZ (update speed) and bitspeed (2400-57600bps). I also think it is a problem that the NMEA is rederected to NMEA183. What about NMEA 0180, 0181, 0182? I think we should link to IEEE RS-422 standard --Steinmb 04:03, 9 August 2007 (UTC)

[edit] Important Error in Protocol Spec

The article specifies that a NMEA-0183 sentence is terminated with a <CR><LF>.

THIS IS NOT CORRECT!

There is NO <CR> specified in the official document. A NMEA-0183 sentence is terminated by a <LF> ONLY. (In Unix-speak, this would be a Newline, the canonical Unix line terminator.) Software that expects to find a <CR> will be rudely surprised when it attempts to process real NMEA-0183 data. —Preceding unsigned comment added by 67.98.153.113 (talk) 16:23, 25 January 2008 (UTC)

Actually, the <CR><LF> terminator is correct. I have a copy of the 1994 NMEA 0183 Standard in front on me, and I can clearly see several places where this is specified. For instance, see page 9 of this version, section 5.3, last paragraph. It's been like this since I care to remember. Also, I'd like to point out to everyone that the checksum is OPTIONAL for most data sentences unless specifically required by the individual data sentence (like RMA, RMB, RMC). —Preceding unsigned comment added by 75.127.151.42 (talk) 20:14, 4 February 2008 (UTC)