The RadioPort™ hardware was designed from the beginning to be easy to use, yet powerful, and flexible. From our first prototype in early 2004 until today, we've paid careful attention advancing the state of the art in rig interfaces.

The RadioPort's audio paths are designed to maintain signal integrity and to simplify setup. We've avoided the usual trim pots and external knobs, because our own use of sound card interface boxes convinced us that audio setup, like other rig interface parameters, should be entirely under the control of the computer that is being used to encode and decode the signal. So we selected a wide-dynamic range sound card chip, and coupled it with digitally-controlled attenuators that add another 60dB of control. Out-of-band filtering helps to clean up your rig's audio before it is sampled, helping to avoid ailasing. High quality transformers are used for full galvanic isolation in the audio path, and a precision voltage reference is used in the analog signal path to provide accurate trimming, sampling, and USB power supply isolation. And, of course, there are separate voltage regulators for the digital and analog sections of the circuit, with single-point ground interconnect between them.

The RadioPort's control paths are equally sophisticated. A re-flashable microcontroller along with the re-flashable sound card-on-a-chip provide added protection from obsolescence to the customer as well as the potential for future software and hardware enhancements. The control subsystems inside the RadioPort communicate via an I2C bus which is accessible via the RadioPort Manager application on the PC, providing excellent real-time control over the audio path (trim pots, sound card chip) and the signaling logic. A complete USB subsystem including an internal hub, two USB to serial ports, and two uncommitted ports provide simplicity of software setup and future expansion possibilities. Full isolation from the rig is maintained by optoisolators and optical relays. Even the optional CI-V interface maintains full isolation by using an internal, galvanically isolated DC to DC converter to power the interface.

Looking ahead, the RadioPort is equipped with an internal mezzanine connector that offers the potential for expansion. The connector provides isochronous digital audio paths to the sound card chip, the two uncommitted USB ports, and the internal I2C bus. Details about how to build mezzanine cards will be released in the future.

The RadioPort also includes hardware and firmware support for EchoLink™. Dual-tone multi frequency (DTMF) decoding is done in hardware under crystal control. These decoded signals are passed back to EchoLink. In addition, the "C" and "D" commands operate an optical relay in the RadioPort, offering the possibility of turning on and off other equipment in your repeater room or shack.

What about all of this re-flashable hardware? Again, in the spirit of keeping things simple for the customer, re-flashing is done through the RadioPort Manager over the internet. More details are available in the description of the RadioPort software features.

We believe that a nice design can be ruined by poor packaging. So we chose a high quality extruded aluminum enclosure for the RadioPort, with professionally printed front and back panel overlays. The RadioPort is mechanically simple and rugged, with a minimum of user interface fussiness. Because power is delivered by USB, no power switch is needed. Because all the trimming is under the control of the RadioPort Manager application, there are no external knobs. A single front panel switch is provided which open-circuits the TX control line, giving you unquestioned "control operator" authority over your transmitter.