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[hill887]

I'm thinking of feeding a GPS as well as a UPS with the NMEA signal from a MR-350.  I can use a ps2 jack to separate the wires onto a strip, and then feed these wires to the devices.

I'm pretty sure that NMEA standard allows for this.

Can the MR-350 feed multiple listeners?
Is there a limit?

One idea would be to feed a PC as well.

Any suggestions on how to implement it?

Do you know of a way to have the MR-350 feed an ethernet hub?

[GS_TECH01]

Just a couple of questions about this:

1.) Do yo plan to utilize the MR-350 with multiple programs at the same time in one computer?
If so, you can take a look at the xPort program (http://www.curioustech.net/xport.html). This would only work in 32-bit systems. You can also refer to this software called GPSGate (http://gpsgate.com/).

2.) Or, do you want to use the device with several computers simultaneously? Please confirm.

3.) Also, what do you mean by UPS with the NMEA signal?

4.) What kind of multiple listeners do you want to test with the unit? Provide some datasheets or specs.

5.) Another thing, what do you plan to do in having the MR-350 feed an ethernet hub?

[hill887]

1.) Do yo plan to utilize the MR-350 with multiple programs at the same time in one computer?

  Not with multiple programs, but with different devices.  But I will look at those utility programs.

2.) Or, do you want to use the device with several computers simultaneously? Please confirm.

   Perhaps several computers.  This would be for a boat, eventually I might put together a
low power usage 12V PC, perhaps running Linux.  For now I use a laptop.  It would be great
for development to be able to use more than one PC.

3.) Also, what do you mean by UPS with the NMEA signal?

    Ooops.  Don't know why I typed those letters, could be age.  By gps I meant a plotter, which
is boat terminology for a GPS display, which get's its location data by NMEA.

4.) What kind of multiple listeners do you want to test with the unit? Provide some datasheets or specs.

There are lots of boat electronics such as a wind meter, gps plotter, radar, autopilot, and even VHF radios
which can accept long & lat over NMEA.  raymarine.com has tons of spec sheets.  Also Garmin.

One issue is that boats are generally 12V as a power source, but I think NMEA signaling can be at much
lower levels.

5.) Another thing, what do you plan to do in having the MR-350 feed an ethernet hub?

Just thought it might be an easier way to share data across devices.  It would certainly help for PCs.  There definitely are some marine electronics which connect over ethernet.

[GS_TECH01]

Please refer below for my response:

1.) Got it.

2.) We have not personally tested the unit with multiple computers, but you can take a look at one function of GPSGate: (http://gpsgate.com/support/sharing_gps_data_over_a_network_and_between_computers).

3.) This unit should work with a NMEA-compliant software. You can contact the manufacturer about this.

4.) For connecting the device with a VHF Radio, refer to this posting: (http://www.usglobalsat.com/forum/index.php?topic=3889.msg10639#msg10639). As for the other boat electronics, please check their schematics and refer to the MR-350 datasheet to see which pin goes to.

If you're planning to us 12V as a power source, please make sure to take a look at this forum posting: http://www.usglobalsat.com/forum/index.php?topic=3951.0

5.) Need to check with our engineers about this.

Furthermore, keep in mind that splicing the cable of the MR-350 would likely void the warranty.

Let us know if you have any questions.

[GS_TECH01]

Hello hill887,

Based on our engineers, the MR-350 cannot be used with an ethernet hub. Also, they pointed out the GPSGate cannot be used in Linux (http://gpsgate.com/download).

Let us know if you have any questions. Thanks.

[hill887]

I connected to the MR-350 via a ps2 breakout cable with 5V power and ground pins connected, and attempted to read the NMEA output on the TX pin.  I was surprised to that what appears to be changing data is at a negative voltage.  Have you seen this issue?  I determined the data pins from your tech page listing the pinout for the female jack.  Might I have VCC and ground reversed?

[GS_TECH01]

Just a couple of questions:

What do you mean by 'changing data'? Please provide more details about this.
What is the value of the negative voltage?
Also, can you please provide the link where you found the pinout connections for the female jack?

[hill887]

Just a couple of questions:

What do you mean by 'changing data'? Please provide more details about this.
What is the value of the negative voltage?
Also, can you please provide the link where you found the pinout connections for the female jack?

Pinout was here:
http://www.usglobalsat.com/store/download/58/mr350p_ds_ug.pdf

By changing value, the voltage level change often, like every 1/4 second.  But the numbers were negative
while other the NMEA outputs on my other devices are positive values.

 

[GS_TECH01]

Got it. By the way, if you're planning to connect the PS2 of the unit to another PS2 of a cable set, you need to have this proprietary cable set: (http://www.usglobalsat.com/p-228-br305-rs232-rs232-cable-set.aspx#images/product/large/228.jpg). In short, other cable adapters would not work.

[hill887]

OK, but I'm not looking for a cable adapter.  The MR-350 transmits NMEA data and I plan to interface it to a VHF radio which accepts NMEA in.  Very straightforward.  Or at least it should be.  ;-)

Getting back to my question:

I connected to the MR-350 via a ps2 breakout cable with 5V power and ground pins connected, and attempted to read the NMEA output on the TX pin.  I was surprised to that what appears to be the NMEA data is at a negative voltage. 
Have you seen this issue? 
I determined the data pins from your tech page listing the pinout for the female jack.
 Might I have VCC and ground reversed?

[GS_TECH01]

We have one customer that was able to interface it with a VHF Radio. You can possibly look into this forum posting: http://www.usglobalsat.com/forum/index.php?topic=3640.msg9576#msg9576

By the way, can you please provide the following information:
What is the serial number of the unit? It should be located at the back of the unit.
Where did you bought it from?
What is the date of purchase?

[hill887]

We have one customer that was able to interface it with a VHF Radio. You can possibly look into this forum posting: http://www.usglobalsat.com/forum/index.php?topic=3640.msg9576#msg9576

By the way, can you please provide the following information:
What is the serial number of the unit? It should be located at the back of the unit.
Where did you bought it from?
What is the date of purchase?

I purchased it 2 1/2 weeks ago from an electronics store in Toronto.  As for the serial number, I would have to climb up the boat in the yard, undo the nut to check it for the serial number.  A lot of work but I could do it if you'll agree then answer my question.

[hill887]

I purchased it 2 1/2 weeks ago from an electronics store in Toronto.  As for the serial number, I would have to climb up the boat in the yard, undo the nut to check it for the serial number.  A lot of work but I could do it if you'll agree then answer my question.

My mistake on the pinout.  Just to help anyone else: The "trick" is realizing that when you connect the female jack to the male, the pin numbers get reversed - the female is a mirror image.   Pin 1 on Female does NOT connect to Pin 1 on the male.  So I had power reversed, thus the negative output.  But I must admit that I'm a little put out by the serial number question.  As if I'd be asking questions about connecting the device if I didn't have one...

[GS_TECH01]

Per our engineers, the negative voltage is considered normal since the MR-350 has RS232 output. Please check the diagram below:

[hill887]

Just to follow up, the mirrored pinout issue had me looking at the RX instead of the TX.