DIY DB9 to RJ45?

[n3fta]

I found an old nano2 lying around but cannot find the dongle. Now if I'm not mistaken the dongle for the Nano2 is just a db9 to rj45 adapter, correct?

If it is just db9 to rj45 is it possible I could make my own db9 to rj45 adapter? I have already tried a couple times but no luck yet, unfortunately my volt meter is out on loan and I cannot test voltages. Anyway below is a pic of the wiring diagram I'm following but I'm not sure if it's correct. See pic below.

17820

My db9 (null) has only 3 wires. Based on what I've found the pinout is as below.

Red: Pin 3
Black: 1
Yellow: 5

As you can see pin 1 is not used in the image above so this is where I'm getting confused. Any help would be greatly appreciated.

[jvvh5897]

Um...I believe that you need a conversion from the +-12V signals on the rs232 port to the current direction system signalling used in CAT5 ethernet. The dongle has a little plug that has that conversion inside it--looks like a regular plug but does a little more. Now, +-12V signals are in effect a current direction signalling too, so I would think it would not take much to convert, but I would do a search on the web to see what some other folks have tried.

[n3fta]

Thanks. I figured I was missing something.

[bkr™]

I have never seen this drawing of a RJ-45 to DB-9 connection.

All I have ever seen is (using the color code of your RJ-45 connector) which is correct in this connection.
This for DTE
RJ-45 DB-9
#5 white/blu pin 2
#4 blu pin 3
#3 white/grn pin 5

This for DCE
RJ-45 DB-9
#4 blu pin 2
#5 white/blu pin 3
#6 grn pin 5

pin 2 and 3 are used for RX and TX on the DB-9 and pin 5 is used for ground

You can go here for all type of connector pin outs used;

http://www.interfacebus.com/Design_Connector_RS232.html

[jcbcd01]

here is another photo you might want to take a look at hope it helps
17821

[bkr™]

Yes I knew that drawing was someplace, duplicates the DTE pin outs I posted in #4 above.

[Terryl]

WOW stop guys, N3fta, just what are you trying to do???

If you are trying to connect the receiver to the router or ethernet by the RS-232 DB-9 connector on the back of your receiver then the connections shown in the photos are wrong.

Most of the dongles have an interface to convert the signals from the ethernet RJ-45 to RS-232 signals, you cant go directly from one to the other, it will FUBAR the router or the receiver.

As JVH5897 mentioned in his post, RS-232 signals run at +- 12 volts DC, ethernet at a much lower level, the two should never ever be directly connected, not without an appropriate interface device or on-board the receiver IC chip.

Some receivers have been factory modified to use the UN-used pins on the DB-9 connector on the back, the connections are different the RS-232 protocols.

[yappapi]

if it matters...
the nano2 used an adapter to connect to a cat5 cable.
so it's not really a dongle if that makes a difference..

[torpainter]

Many attempts were made to make one with no success

[jvvh5897]

I had forgotten about the dongles that used pins other than the 2/3/5 on the 9 pin connector--think those actually used ground and +5V as signal levels and had to provide a +5V power source for the connector in the dongle. Dongle connector might have been designed to split the cat5 signals into a received line and transmit line too--the cat5 signals have RX and TX on the same line pair if I'm remembering right. And the idea of "baud" and start and stop bits with or without parity, is not one used in cat5 signals either, so the 115kbaud of an rs-232 port is not something that an internet provider function with.

[ChillyWilly]

Many attempts were made to make one with no success

Actually some people figured out how to do this, but rather than posting their results, they sold the sold the adapters


http://www.amazon.com/Dongle-Adapter-Ethernet-Ready-original/dp/B00960HAR6


http://www.clasificadosonline.com/UDMiscDetail.asp?MiscIdNumber=5739966

[torpainter]

Actually some people figured out how to do this, but rather than posting their results, they sold the sold the adapters


http://www.amazon.com/Dongle-Adapter-Ethernet-Ready-original/dp/B00960HAR6


http://www.clasificadosonline.com/UDMiscDetail.asp?MiscIdNumber=5739966

People who bought these reported they did not work

[ChillyWilly]

People who bought these reported they did not work

I'm thinking they worked with some routers but not all. These simple straight wired adapeters do not have the magnetic buffers contained in the the factory adapters, so it's possible they worked with some routers and not with others. However it would be nice to have a wiring diagram for them....after all they're using a $2 adapter, so it would be worth a try

[torpainter]

I'm thinking they worked with some routers but not all. These simple straight wired adapeters do not have the magnetic buffers contained in the the factory adapters, so it's possible they worked with some routers and not with others. However it would be nice to have a wiring diagram for them....after all they're using a $2 adapter, so it would be worth a try

All the diagrams and wiring diagrams were lost when the database was purged There was a very long thread with all the info,pics,adapters that had been opened. A lot of people with way more knowledge than I could ever hope to have tried and failed....lol
Its not a $2 adapter

[ChillyWilly]

All the diagrams and wiring diagrams were lost when the database was purged There was a very long thread with all the info,pics,adapters that had been opened. A lot of people with way more knowledge than I could ever hope to have tried and failed....lol
Its not a $2 adapter

The $2 part is what the those guys are using to make the homemade adapters, sorry if I wasn't clear.

And sorry things got purged, but here's something I picked up a while back

18003

[bkr™]

That is the one I was trying to find...thanks, I knew it was someplace.

[WatchingTV]

This is what you want to build for the Nano2 and only for the Nano2

[bkr™]

I see 1 cap and 1 something...perhaps a coil? Wow this is different, thanks just more info.

[Terryl]

This is what you want to build for the Nano2 and only for the Nano2

Thats not the right schematic for that interface, it's missing a bunch of stuff.

The RJ-47 connector has internal transformers to isolate the connections and block the DC voltage/currents on the signal buses but pass the AC signals to the receiver.

With out the right RJ-47 connector the system can be damaged.