LAN connection without dongle on WM8650 tablet

When using a LAN connection with a tablet that hasn’t the RJ connector on-board, you can have some problem to gain the Heaven, ‘cause very often the “dongle” with the attached LAN cable detaches from the tablet, breaking all the connections (and probably your active work) and you, in such situation, may automatically start a sequence of @#@#@# and @@#@#@ that are not good to make points to your future “seat” up into the Sky.

So, what’s the simplest way to add an RJ connector to a tablet that hasn’t one ? It’s very simple : open the tablet and look for the transformer. Every tablet I’ve seen has all the circuitry inside, just the connector is outside, on the dongle. The transformer is the better place to solder wires, ‘cause has (usually) the pins spaced of 1.27 mm that is a measure easy to solder. In this picture, you can see one model of these transformers :

Even if your model is different, you will always have four small wires (look at the red arrows in the image) that comes from the “black bug” and go to the dongle’s socket. In my tablet’s specific case, the pins are named this way :

  • pin 16  RX + goes to RJ45 connector pin 6
  • pin 15  RX – goes to RJ45 connector pin 3
  • pin 10  TX + goes to RJ45 connector pin 8
  • pin  9   TX – goes to RJ45 connector pin 7

To clarify what are the positions of the pins on the RJ female connector / socket, here is a picture of the one that’s normally placed on the tablet’s dongle : note that the pin 1 is at the left ; the pinout suggested in the list above uses this standard.

Note that the pairs RX and TX are always “physically separated” (it’s a transformer !), so if in doubt when connecting a different type, consider that the TX and RX pairs are : one on a side, the other on the opposite. Also note that all the components on the circuit, needed for a correct ESD protection, are not mounted. It’s for sparing some money. In the practical use, if you just connect the tablet to a 1 meter cable tied to a router or another PC, you don’t need for it. Remember : you’re playing with very cheap devices. Anyway… soldering isn’t difficult, look here how I connected 4 wires of typical flat cable :

Not too difficult… and now, on the other side, I connected the RJ45 socket that will be used as tablet’s LAN connector. After testing the connection with success, use something like hot glue to make it “solid” and electrically insulated.

And finally, using a normal 1,5 meters LAN cable, I connected the tablet at my router and gained access to Google, as you can see in this final picture (note that wifi isn’t enabled !)

If you look a little bit deeply, you can see also other 2 cables coming out from the tablet… One is the serial port that actually is connected to IR led to work as remote control for my Sony TV, and the other is an USB female port, active and working (but unconnected in this picture), that I often use for my wireless KB / Mouse. Obviously… I hate tablet dongles 🙂