Modify powerline (EOP) adapter to phone wiring


Getting connections to hard to reach places where powerline adapters don't work or work poorly. 
Garages and granny flats. Any place you have phone wiring (or any sort of wiring for that matter). 
Some of us have old coax cable or even better slow ethernet cable.. cat5 for example with perhaps only 10mbit working. 
Intercom cabling.. which is probably just phone cable.. security cabling again much like phone cable. 

Powerline (Ethernet Over Power or homeplug in US) adapters are readily available and work fairly well depending on the power wiring in your house. 
In some places you can buy very similar devices to use over phone lines or over coax for cable TV. (MoCA connectors in US). 
All of them use the same basic technology as does Extended Ethernet and VDSL. 

You can buy these Extend Ethernet adapters for several hundred dollars.. and yet.. why are they so expensive when EOP are now so cheap. It is simply competition and sales volumes. 

In Australia we can get powerline adapters fairly cheaply.. and it should not be that difficult to get them to work over any sort of cabling.. since power cable is about the worst transmission environment you could find. 

I found an article which got me going.

There are much better units available now since that article was written. Powerline is available now in MIMO although most are still SISO (ie single in single out). MIMO units will need two pairs to work to full speed potential.. and the units will be larger and more expensive. SISO units are available up to the so called 1000Mbps.. Here you can buy one of the standard AV500 units second hand on ebay for $50 or less. 

There are units with speeds advertised as 2000.. of course the lies just keep getting bigger. In reality you will never achieve 2000Mbps in any real world.. not even half that. 

Powerline specs are a cheat.. much like wireless the marketing department are always thirsty for the biggest numbers.. "mine is bigger than yours!!" is the curse of the planet. 
Gigabit ethernet is duplex 1000Mbps in both directions.. in powerline terminology this would be 2000Mbps.. ie they are adding TX and RX .. 

So a set of AV500 will actually work at 250Mbps in one direction. My testing indicates that they tend to be faster in one direction than the other .. which makes sense for Internet connection since most of us will be on much higher download than upload speeds. 

So what to buy.. ones that are easy to disassemble using screws through the base piece to the upper body.. and speed fits your needs. 
For example powerline without a plug through are great.. whereas if you use them over actual power having the plug through is a big help since they often occupy a double power point. 
Tiny micro versions are to be avoided.. you need space to solder connections.. the closer packed the circuit the harder it will be to modify. Big is good for this exercise. 

Buying second hand is fine. Since you are going to smash them warranty may not be easy to get if you damage them. 

AV500 is about the min I would buy.. but most have 100Mbit ethernet ports.. so the speed over cable can never exceed that number. (due to the number of lies being told this limitation is minor). 

However if you want higher speed you must buy ones with gigabit ethernet ports. These could also be called AV500 or AV600 or even AV1000. Any of the MIMO type AV2 standard will be gigabit. 

F5D4085 v1 AV500 but with gigabit ethernet. 

 I got a pair of Belkin AV500 with gigabit ports. F5D4085 v1 second hand and ugly looking.. all the better from my point of view because they were cheap. 
It is screwed together and so come apart easily.
First step then is to open the unit.. 

Now this is the difficult bit and you might want to wait before you fully remove the board.. we need to discover the DC power supply voltages that are generated by Adapter.. Now if you have no idea.. or experience with live power items.. stop now. I think if you send me a pic of the unit board I can guess the voltage..  

Apparently it is common to use a transformer with two windings.. 
A 3.3v which is to drive the electronics.. and a 9-12v supply to the Tx side for transmission. This is a small nuisance as it means we need to supply two voltages. You also then need to figure out where you can supply that on the board. 

There are multiple choices here though.. depending on what you want to achieve. 

I also measured all the voltages through the pin connector between the two boards. 

1-2 Blue winding T2

4, 6 White winding T2 

3, 5 NC

7,8 GND

9,10 3.3v

11,12 GND

13,14 9.25V

Back of the power board. 

At top is the Tx and Rx from the original power plug. I am testing here with a piece of coax. 

Below the white label is the DC low voltage side.. above is high voltage AC side. 

I powered it using external power supply.. set at 9v .. Yellow and blue is GND wire. 

Plus a KISS33 module to produce 3.3v common Gnd with 9v and Red for +3.3v. 

Other side of the power board.. you can see the largest component is transformer in around the centre of the board right side of the board. 

This is the data side showing the 14 pin connector between the boards. 

It does make life a bit easier having the two parts separate.. parts are not so packed together. 

The toroid transformer used for connection between data side and power side is also visible in this shot. 

It has two windings on the secondary side.. one is Tx and one Rx .. with one winding on the primary side. 

Windings are just a few turns of wire.. red, white and blue. Red power side.. very patriotic. 

So power to the data board.. and the actual link to the power circuit we have figured out. 

The rest is easy peasy.. use any wire you like.. phone wire twisted pair is great. over 200M ie 600FT you should manage full speed.. 

You can even put the transmission power up a bit.. I increased the 9v supply to 12v and consumption went from 3.5W to around 5W. Be careful though to make sure it does not overheat. 

Just a few quick results.. 

Over 20M of 50ohm 10base2 coax

Over a single or double pair of cat6 nearly full box connected each end.. 275M or 900ft

This is pretty good result.. and it really did not make any difference using one pair or two doubled up.. that will change when I test the MIMO units next week. 

Basically you can achieve 100Mbps fairly easily .. 

I thought using a DC bias on the wire would help but it seems to make it worse.. So much better to power each end rather than running power down the cable.. POE style. 

D-Link DHP-700AV Early series AV2000

My next experiment turned up.. very nice white shiny plastic.. very easy to open.. undo four ordinary and tiny phillips head screws and it falls apart. 

D-Link used a single board for power supply and control electronics. And it shows the development in the chipset from 2011 with AV500 standard to the 2015 AV2000 standard. 

You can easily see the same components on each unit.. The large transformer in the middle right of the board to provide DC power.. in this case 3.3v and 12v. So easy for us to duplicate. 

Instead of single toroid transformer there are two transformer in bottom left view.. as this unit is MIMO.. so will use Line + Neutral and Line + Earth pins. 

The transformers are neater, smaller encapsulated units. 

Here is the test results same 275M 900ft cat6 with two pairs. 

And Macbook end

This is with both ends running at the same time. 

It clearly works better than the original AV500 by a fair margin.. although in one direction not both.. even if the D-Link were never rated very highly in their original EOP form. 

I will keep my eyes open for a very cheap set of AV500 netcomm adapters which are very common here.. so people can easily buy them to modify. 

Talk to me.. if you have questions.. this is the first post.. I will add more as time goes on and I develop other units to add to the KB. 
Or if other people do trial it with different models we can show how to modify to other people. 

Note I blew up one of the D-Link units.. just poor soldering on my part.. so be careful.. though not expensive it always is a pain to destroy what you were working on.