Switched output on 5212

Forrestkk

Forrestkk

Well-Known Member
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May 1, 2021
782
Emerald Coast of Florida
Boat Info
1999 450 Express Bridge
Garmin 5212s, Garmin HD Radar
Raypilot 650
Engines
Cummins 6CTA.8.3M 430 HP
ZF 280-IV Transmissions
Hi All,

Odd question here on some older electronics.

I have a Garmin 5212 (https://www.garmin.com/en-US/p/9158) which is wifi compatible, not capable. I found a wifi adapter on ebay (https://ph.garmin.com/mobile/products/discontinued/garmin-marine-wi-fi-adapter-kit/) and have physically installed the system, but to power the POE adapter I need to find a trigger wire that will activate a relay to power the adapter when I turn on the 5212 chartplotter.

I could put it on a separate switch, but that is a bit clunky. Does anyone have an easy answer on a best practice do have something turn on when the chart plotter is turned on?

Thx in advance!
 
Last edited:
Couple of questions first
Do you have a Garmin Ethernet switch ("Port Expander")?
An off the shelf Ethernet switch?
Or a direct Ethernet cable ?
Is the Ethernet cable a Garmin or an off the shelf cable?

Reason being is while Garmin uses Ethernet for the data, they do NOT use all the standard pins in the normal networking manner.
Garmin Ethernet is 10 Megabit full duplex, that only needs 4 of the 8 available Ethernet wires in the cable.
Garmin Ethernet cables are all wired for "cross-over" meaning at each end certain colors a flipped (Tx->Rx/Rx->Tx)
Garmin Ethernet do not cross all the wires the non-data wires are straight thru (not crossed)
Garmin uses one wire as a "switch to ground" to tell all the other Garmin devices on the network to come out of standby and power up. (like the Radar)

Confused yet?

Pin #5 taken to ground by the MFD is the signal wire to tell the network devices (Radar, Sonar Box, WiFi?) to turn on.
The attached PDF is the Garmin wiring for their Ethernet cable.

If you use a standard Ethernet switch it does not pass that pin #5 thru to the other ports.
A standard switch uses those extra pins for more data
A standard Ethernet cable wont have the correct pin to pin to pass data and the power signal.

I have made a custom control out of a cheap un-powered POE injector, if needed, because I use both a Garmin EchoMap and an OpenCPN navigation PC.
The GRadarDoc PDF is about a home made switch to energize the devices, radar specifically.
 

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Last edited:
hughespat57 said:
Couple of questions first
Do you have a Garmin Ethernet switch ("Port Expander")?
An off the shelf Ethernet switch?
Or a direct Ethernet cable ?
Is the Ethernet cable a Garmin or an off the shelf cable?

Reason being is while Garmin uses Ethernet for the data, they do NOT use all the standard pins in the normal networking manner.
Garmin Ethernet is 10 Megabit full duplex, that only needs 4 of the 8 available Ethernet wires in the cable.
Garmin Ethernet cables are all wired for "cross-over" meaning at each end certain colors a flipped (Tx->Rx/Rx->Tx)
Garmin Ethernet do not cross all the wires the non-data wires are straight thru (not crossed)
Garmin uses one wire as a "switch to ground" to tell all the other Garmin devices on the network to come out of standby and power up. (like the Radar)

Confused yet?

Pin #5 taken to ground by the MFD is the signal wire to tell the network devices (Radar, Sonar Box, WiFi?) to turn on.
The attached PDF is the Garmin wiring for their Ethernet cable.

If you use a standard Ethernet switch it does not pass that pin #5 thru to the other ports.
A standard switch uses those extra pins for more data
A standard Ethernet cable wont have the correct pin to pin to pass data and the power signal.

I have made a custom control out of a cheap un-powered POE injector, if needed, because I use both a Garmin EchoMap and an OpenCPN navigation PC.
The GRadarDoc PDF is about a home made switch to energize the devices, radar specifically.
Click to expand...

@hughespat57, thx!

I do not have a port extender.

I do not have a standard ethernet switch.

I have two standard ethernet cables. One from the POE box to the pico station and one to the 5212.

I did not realize the Garmin cables were null modem wired (yup, I remember null modem serial cables).

No, not confused.

I'm curious if I swap out to a Garmin ethernet cable from the 5212 to the POE if it will switch on and off as you describe? From the POE injector to the pico station the cable type shouldn't matter???
 
Last edited:
I would think the POE to Pico is standard or wouldn't matter.
Most real Ethernet network devices today (switches, AP, etc) have auto detection for Rx/Tx and will self adjust.

Not a true full crossover so watch the pin layout in that document if you fabricate your own cable.
 
Forrestkk said:
@hughespat57, thx!

I do not have a port extender.

I do not have a standard ethernet switch.

I have two standard ethernet cables. One from the POE box to the pico station and one to the 5212.

I did not realize the Garmin cables were null modem wired (yup, I remember null modem serial cables).

No, not confused.

I'm curious if I swap out to a Garmin ethernet cable from the 5212 to the POE if it will switch on and off as you describe? From the POE injector to the pico station the cable type shouldn't matter???
Click to expand...

Holly crap; and I though I was doing something when I got my 4210 talking to the Simrad auto pilot.
 
Forrestkk said:
@hughespat57, thx!

I do not have a port extender.

I do not have a standard ethernet switch.

I have two standard ethernet cables. One from the POE box to the pico station and one to the 5212.

I did not realize the Garmin cables were null modem wired (yup, I remember null modem serial cables).

No, not confused.

I'm curious if I swap out to a Garmin ethernet cable from the 5212 to the POE if it will switch on and off as you describe? From the POE injector to the pico station the cable type shouldn't matter???
Click to expand...

Not answer for @hughespat57 but here is how I have this working and it does work just fine as hughespat57 describes. Just a little added clarification.

You need to use the GMN cable as they have it wired coming off of the GMN, make one yourself or buy a Garmin one. The POE injector will allow you to pull the voltage off of the GMN and use that to turn on device from that voltage, might need a relay depending how far you go with turning things on/off. But you can only use a standard ethernet cable after the injector. This method does work great and I use it to interface to the Fusion radio with a standard network switch.

If you want to pull the voltage off from the cable without the injector, use pins 4,5 and 7,8 that will give a 12v signal.
 
Last edited:
SKybolt said:
Not answer for @hughespat57 but here is how I have this working and it does work just fine as hughespat57 describes. Just a little added clarification.
You need to use the GMN cable as they have it wired coming off of the GMN, make one yourself or but a Garmin one. The POE injector will allow you to pull the voltage off of the GMN and use that to turn on device from that voltage, might need a relay depending how far you go with turning things on/off. But you can only use a standard ethernet cable after the injector. This method does work great and I use it to interface to the Fusion radio with a standard network switch.

If you want to pull the voltage off from the cable without the injector, use pins 4,5 and 7,8 that will give a 12v signal.
Click to expand...

@SKybolt, thx!

Plan on buying a Garmin cable to go from 5212 to POE injector. To clarify, you are saying I should splice into pins 4/5 and 7/8 to drive a relay? Or is it just one of them by pair like blue and blue white (4,5) or are blue/blue white both positive and brown/brown white both negative? Assuming I only need positive to trigger the relay as I can ground directly to battery negative (less splicing).
 
Forrestkk said:
@SKybolt, thx!

Plan on buying a Garmin cable to go from 5212 to POE injector. To clarify, you are saying I should splice into pins 4/5 and 7/8 to drive a relay? Or is it just one of them by pair like blue and blue white (4,5) or are blue/blue white both positive and brown/brown white both negative? Assuming I only need positive to trigger the relay as I can ground directly to battery negative (less splicing).
Click to expand...

Pins 4,5 and 7,8 are the POE voltage pins, I believe 4,5 are + and 7,8 are -. Only TTL or ~100ma, it's only a signal. But there are plenty of 100ma driven relays that can then drive others. I think I have the polarity right for the pins, that is what the standard is for POE adapters, but it does work. If you are using a GMS 10 in the mix, use the extra port out of the 5212. I am not sure the GMS 10 transfers the voltage or not, I believe it does, just don't remember. Sorry. I can check this weekend when I am at the boat if you like.

Here is an example of a 100ma activated relay that can power up to 10A.
https://www.amazon.com/AEDIKO-Chann...5?keywords=DC+12V+Relay&qid=1636659861&sr=8-5

This would put the voltage on the power connector very easily, just a little testing to get it right.
https://www.amazon.com/POE-IO-135-P...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

I believe the bottom POE connector plugged in to the GMN cable would give you 12v. Cut the power lead off of the other POE cable (after you verify the voltage) and connect that to the relay PCB and your done. I did something very close to that my self. I would not separate the grounds or power coming from the 5212 as that may cause other issues or damage the display.
 
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