I recently heard that the DX Doubler (DXD) SO2R Controller by TopTen Devices, has been discontinued. Looking at their Web Site, it has completely vanished, along with the Radio-specific cables, User Manuals, etc. This controller was a great addition to my shack a few years ago. It is a very simple design, with no Microprocessors involved, and is not only useful for SO2R use, but also a fine centerpiece in a two-radio shack for everyday operation. Given its Parallel Port interface, it is understandable that the DXD box could not be expected to compete with more modern USB-based SO2R controllers. Unfortunately, these newer designs appear to be much more complex and fairly expensive. I will continue to use the DXD boxes in my station for now, but will start looking at an eventual replacement.
As you may know, I have designed a USB interface for the DXD and will wrap-up that activity in the near future (update – completed long ago). I plan to go ahead with the final version of the PC Board layout for the DXDUSB, as the project has been a great learning tool, and I would hate to leave the project unfinished. The resulting board is really a general-purpose Arduino-based decoder for the Open Two Radio Switching Protocol that is supported by SO2R controllers. I hope to be able to use it in some other Contest-station supporting roles in the future. It may be useful as a Band decoder for some radios, or for interfacing of older radios with modern Contesting software such as N1MM+.
It does seem unfortunate that all signs of support for the DXD seem to have disappeared, considering that it was still being sold just a couple months ago, but I will be looking forward to future product offerings from the folks at TopTen.
August 1, 2018 Update
I continue to use the DX Doubler in my station, as do many others. Even after it was discontinued, I rarely see one for sale. The only concern with using this now-discontinued box is that the rig-specific cables are no longer available commercially. Since the interfaces are all audio connections, it is not very difficult to make your own. I have mounted one of my DXDUSB interfaces inside of my DX Doubler, so I now have what is probably the only DX Doubler anywhere that has a “native” built-in USB interface. It works great for me.
The DXDUSB has been completed and I now have several people also using it to allow them to interface to their DXD using only a USB port, including a few International users. This has been an interesting project. A new version of the PC Board has now been produced, that can be used for Band Data decoding, to allow using N1MM+ software to output the data needed to drive peripherals like a 2X6 antenna switch. This is still in the initial debug stage. It will allow me to provide customized or K3-compatible Band Data signals for switching 2 radios to any 1-of-6 antennas.
There are two well-know alternative commercial SO2R boxes that you can buy; the Microham and the YCCC SO2R controller. I have no experience with either of these. What I hear is that the Microham line is very flexible and also very complicated, using many Ports for computer connection. The YCCC box looks a bit more like the DX Doubler to me. I have considered getting one of these, but for now I will be sticking with my DX Doubler.