[CA] [CA11] AIS650 NMEA Issues

[grahamopenshaw]

I have been successfully using the 4800 NMEA output from my 650 to provide position to my Raymarine VHF for several years. For some reason that I cannot remember I had the unused high baud inputs and outputs connected to one another although I can see nothing in the manual to suggest I do this.

I now want to connect a device to the high baud output but as soon as I separate the wires the 4800 output stops working.

Any ideas / solutions? I have updated the firmware - no change.

Thanks

Graham

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Graham,

The only reason which I can imagine that one would interface the AIS650's 38400 BAUD NMEA 0183 output leads to its 38400 BAUD NMEA 0183 input leads would be as system in which each of the following conditions exist:

1) the AIS650 had been interfaced to a powered and properly terminated SeaTalkng / NMEA 2000 backbone to which a MFD or i70/i70S MFID responsible for displaying AIS data had also been interfaced; and

2) the 4800 BAUD NMEA 0183 input leads of a DSC VHF radio or SSB have been interfaced to the 4800 BAUD NMEA 0183 leads of a DSC VHF radio or SSB;

3) the AIS650's "Output GNSS sentences" required by the DSC VHF radio and/or SSB have been checked for transmission. These sentences are configured for transmission via the ProAIS2 application.

Doing so will cause an AIS650 which has acquired a GPS position FIX to transmit this data from its 38400 BAUD NMEA 0183 communications port. As its 38400 BAUD NMEA 0183 output port has been wired to its 38400 BAUD NMEA 0183 input port, the received 38400 BAUD GNSS sentence(s) will be multiplexed to 4800 BAUD and then transmitted out of the AIS650's 4800 BAUD NMEA 0183 output port.

Accordingly, it would be recommended that the AIS650 has 1) been updated with the latest available Raymarine product software update and has been configured (use the ProAIS2 software found on the AIS650's software update web page) to transmit the GNSS sentence(s) required by your DSC VHF radio.

[grahamopenshaw]

Thanks Chuck,
What I would like to do is as follows:

1. Provide position to my Raymarine VHF and an icom 802 SSB. I am assuming this needs to be at 4800.

2. Provide AIS data to a Digital Yacht AIS Lifeguard MOB Alarm at 38400.

As I understand it from your note below, even though I am using the 38400 data stream, I still need to connect the 38400 output to the 38400 input to get data to the 4800 output? I think the data structure is OK as the radio was fine until I disconnected the 38400 pass through and the DY sniffer seems to be working fine now (not easy to tell). I have updated the firmware.

Thanks

Graham

[Chuck - Raymarine - Moderator]

Graham,

Q1. Provide position to my Raymarine VHF and an icom 802 SSB. I am assuming this needs to be at 4800.
A1. Indeed, these devices require that GPS data be received from a 4800 BAUD NMEA 0183 data source. All NMEA 0183 transmissions include a two character Talker ID which identifies the type of product from which the transmission was sent. The AIS650 correctly transmits the "AI" Talker ID to indicate that the source device was an AIS transceiver. Unfortunately, many ICOM products will only accept GPS data from a 4800 BAUD NMEA 0183 source which transmits the "GP" Talker ID. In such cases, the solution specified within the FAQ found here is recommended.

Q2. Provide AIS data to a Digital Yacht AIS Lifeguard MOB Alarm at 38400.
A2. Given this requirement, it would be recommended that the solution specified above to provide GPS data to the ICOM communications products be utilized. It would then be recommended that the AIS650's 38400 BAUD output lead be disconnected from the AIS650's 38400 BAUD input leads and the the AIS650's 38400 BAUD NMEA 0183 output leads then be interface to the Digital Yacht AIS Lifeguard MOB Alarm. Unlike 4800 BAUD NMEA 0183 communications which is commonly paralleled to provide data to three or four NMEA 0183 listeners, it is not recommended that 38400 BAUD NMEA 0183 communications be paralleled, as it often yields unreliable communications.

[grahamopenshaw]

Thanks Chuck,
The following is working:
A. 4800 output connected to the Raymarine VHF and the Icom 802 SSB. Both are receiving position and time OK.

B. 38400 output connected to the Digital Yacht Lifeguard AND looped back into the 38400 inputs.

I am concerned about this being potentially unreliable but if I disconnect the loop back on the 38400 then the 4800 output immediately stops working.

Ideas?

Graham

[Chuck - Raymarine - Moderator]

Graham,

Looping through the Digital Yacht AIS Lifeguard MOB Alarm should be satisfactory as long as the Digital Yacht AIS Lifeguard MOB Alarm is designed to re-transmit all received 38400 BAUD NMEA 0183 data. Given that the system is working and that the AIS650's NMEA 0183 output is not paralleled, I wouldn't recommend making any further changes as long as the MFD is receiving AIS data, the Digital Yacht AIS Lifeguard MOB Alarm is receiving AIS data, and the communications devices are receiving GPS data.

[grahamopenshaw]

Sorry,
I was not clear. The loop back is not through the Digital Yacht device as it has no output. The 38400 input is connected to the 38400 output in parallel with the DY device.

Is there a potentially more stable solution?

What I am still failing to understand is why the 4800 output fails when the 38400 is not looped.

Graham

[Chuck - Raymarine - Moderator]

Q1. Is there a potentially more stable solution?
A1. Yes. Please refer to the recommendation provided in Today' 11:15 AM, part A1.

A2. What I am still failing to understand is why the 4800 output fails when the 38400 is not looped.
A2. I addressed this within part 3 of my initial response. In a nutshell, the AIS650's multiplexer's function is exclusively to take NMEA 0183 sentences received via its 38400 BAUD input leads and then transmit these same NMEA 0183 sentence via its 4800 BAUD NMEA 0183 output leads. Should the 384000 BAUD NMEA 0183 output of the AIS650 have been configured to included GNSS sentences (see my initial post), then wrapping the 34800 BAUD output leads of the AIS650 to its 38400 BAUD NMEA 0183 input leads would have then caused these GNSS sentences to be retransmitted via the AIS650's 4800 BAUD NMEA 0183 output leads. Disconnecting the AIS650's 38400 BAUD NMEA 0183 output leads from its 38400 BAUD NMEA 0183 input leads will in essence cause no NMEA 0183 sentences to be transmitted via the AIS650's 4800 BAUD NMEA 0183 output leads.