RS-422 or RS-232 into NMEA

[Hoghead]

My search skills need work, and my eyes glassed over with a couple of the threads I found....

I have a new AIS that outputs RS-232 and RS-422 and want to integrate it into my Ray Es127 MfD that has both NMEA 0183 and 2000 inputs

Is RS422 compatible with NMEA 0183?

NMEA 2000 is preferred - it this possible?

[Paul Elliott]

Which AIS unit do you have? NMEA2000 uses a specific signal format, and somewhat standardized connectors, so if your AIS gadget doesn't have a port that says "NMEA2000" on it somewhere, you can't connect it to the MFD's N2K port without using an adaptor.

RS422 is indeed the interface standard for NMEA 0183 interfaces. You can usually make RS232 work as well.

If you tell us the type of AIS unit you have we may be able to give you more specific advice.

[Hoghead]

Matsutec HA-102

[puffcard]

Be careful about using something not approved by the USCG or the FCC.

[smac999]

Both are nmea 183.

Depends if plotter wants an rx- (ground) or rxb

Sending 232 to either will probably work and no harm. Sending 422 to the wrong one can harm.

[continuouswave]

When interconnecting NMEA-0183 to a RS-232 device, you can consider the RS-232 as just a single-ended NMEA signal.

RS-232 Data TX = TALKER A
RS-232 Data RX = LISTENER A

In RS-232 there are no TALKER B or LISTENER B signals.

RS-422 is a balanced signal:

RS-422 DATA TX = TALKER A
RS-433 DATA TX inverted = TALKER B
RS-422 RX TX = LISTENER A
RS-433 RX TX inverted = LISTENER B

For general advice on NMEA-0183 interfacing using a well thought out, consistent, logical method, see

Guide to NMEA-0183 Interconnections
continuousWave: Whaler: Reference: NMEA-0183 Interconnection Guide

For a collection of many modern marine devices and their NMEA-0183 port data, see

NMEA-0183 Interface Data Collection
NMEA-0183 Interface Data Collection - CONTINUOUSWAVE

For advice on a very useful and convenient connector system, see

Universal NMEA-0183 Interface
http://continuouswave.com/whaler/ref...lNMEA0183.html

[Emouchet]

RS422 versus RS232: this is mostly electrical voltage that makes the difference.

RS422 or RS232 is for send NMEA0183 sentences. NMEA2000 use a different protocol. Faster. NMEA2000 is derivated from CANBUS, the type of databus use in the car industry.

RS422 is using -6v +6v differential voltage range for signaling. So because of the large voltage, it is more resisting to noise when communicating.

RS232 is using non differential voltage, 0-5V AKA TTL.

Typically, you can use adapters to convert in between.

Some people simply wire the RS422 to RS232 by using xmit+/receiv+ and GND rather than xmit+/receiv+ and xmit-/receiv-.

[CarinaPDX]

Originally Posted by Emouchet

RS232 is using non differential voltage, 0-5V AKA TTL.

Not to be difficult, but I believe RS-232 is RTL, not TTL. So is NMEA 2000 and CANBUS. RTL=Resistor-Transistor Logic, where a pull-up resistor is used with a transistor to pull down. TTL, Transistor-Transistor Logic, uses transistors for both pull-up and pull-down; I think RS-422 uses TTL. Its been a long time since I studied this stuff...

For the OP: NMEA 0183 is based on RS-422 so interconnecting the two should work well. Don't jam RS-232 into an NMEA 0183 input, especially since you have the right interface available.

Greg

[Paul Elliott]

RS232 and RS422 are defined by voltage levels, not technology. The circuitry may use bipolar or (more likely) CMOS technology.

RS232 is specified to have a voltage swing between +/- 5V and +/- 15V. There is a signal wire and a ground wire -- this is called "single-ended". For many years +/- 12V was the typical output, with +12 being a logic zero (or "space") The negative voltage was a logic one (or a "mark"). These days, many "RS232" devices use +/- 5V or +/- 10V, and some even use +5V/0V. Most RS232 receivers consider 0V to be a "mark", so the +5V/0V signal, while not standard compliant, will work OK. Usually.

RS422 uses two signal wires -- this is called "balanced" or "differential". The voltage range on either wire is -3V to +3V, and when one wire goes negative the other goes positive. RS422 is relative immune to coupled noise, at least when compared to RS232.

continuouswave describes how to hook up these different standards.

[Hoghead]

My eyes are more glassed over than before after trying to understand. I am in the Philippines and there are no installers here who have a clue so I have to do this myself.

Continuous wave suggests 10 different possible combinations?

Can someone please give me a simple connect this wire to that wire explanation?

[CarinaPDX]

Sorry for the confusion. The best thing is for you to give us the names in the manuals, as they may use different descriptors. You will want the RS-422 outputs from the AIS and the NMEA 0183 inputs to the MFD. There will be just 2 wires needed. Outputs can be labelled talker, data, tx or ? and inputs will be labelled listener, data, rx or ? Both will have a plus (+) and a minus (-) connection, or perhaps data or signal and common. If in doubt just give us the names out of the manual and we can tell you. It is simple to do once you recognize the naming conventions used.

Greg

[clownfishsydney]

Why do you want to connect from RS-232 to NMEA? There are NMEA 0183 outputs in the power cable that you can use.

We have the HA-102 on our dive boat, manual is poor but it was easy to connect.

[Hoghead]

Originally Posted by clownfishsydney

Why do you want to connect from RS-232 to NMEA? There are NMEA 0183 outputs in the power cable that you can use.

We have the HA-102 on our dive boat, manual is poor but it was easy to connect.

I did not see that in the Chinglish instructions - or at least not in my manual version. It is also not mentioned in my specs
What wire does what?

[Hoghead]

I now feel a bit foolish.......

In rereading the manual it is called a power/data cable, and I gapped the data part as I was looking for NMEA 0183 or 2000, and searching for output specs.

There is a terminology difference
AIS uses:
TX+
TX-
RX+
RX-
in addition to SD, RD, SG, and NC

Ray has 2 ports one of which is in/out and the other in only:
Port 1
In+
In-
Out+
Out-
Port 2
In+
In-

How to determine which NMEA version the AIS is using?

Assuming the AIS is NMEA 0183, which AIS nomenclature to which Ray nomenclature?

[CarinaPDX]

I would connect TX+ on the AIS to the In+ on port 2 of the MFD, then TX- on the AIS to the In- port 2 on the MFD.

QED

Greg

Edit: This leaves port 1 for in and/or out usage in the future.