September “Plugfest” Provided First Test of Interoperability 


Nearly 90% of vendor systems succeeded in communicating through 111 different test combinations, proving the functionality of the standard

PISCATAWAY, NJ: 2 November 2023: The Digital Intermediate Frequency Interoperability Consortium  (DIFI) held its first Plugfest – where vendors test the interoperability of their products based on a technical standard – in September at the Kratos Defense & Space offices in Colorado Springs.  In this high-wire event, a standard that just released its version 1.2.0 faced the multi-vendor reality for the first time. The 25 engineers attending tested 13 vendor systems – and despite challenges along the way, nearly 90% were able to communicate, proving the functionality of the standard in providing interoperability among different vendor systems.  The test profiles ranged from low to high sample rates with low to high bit depths – specifically, from 12.5 Msamples/sec at a bit depth of 16 bits per sample, up to 750 Msamples/sec at a bit depth of 6 bits.

Keith King of Wavestream, organizer of the event, credited attendees for making it so successful. “The teamwork on display was really impressive,” he said. “Everyone wanted everyone else to have some successes. If one company was having trouble, the others jumped in to assist.” King also cited the band of volunteers who assisted him.  “I could focus on solving one problem while they were already working to avoid the next ones.”

“The spirit of collaboration definitely made it happen,” said Michael Phillips of Welkin Sciences, one of those volunteers. “There were lessons learned, but the various teams came together and addressed the issues.” Mark Lombardi of Keysight Technologies was another volunteer. “It was truly exciting to see how the hard work of DIFI’s membership produced a giant leap forward for the network transport of digitized IF signals.”

Evertz contributed to success with a local network that allowed multiple receivers to listen to a single transmission simultaneously, and to route anyone’s signal to anyone in the test. It enabled the Plugfest to test 111 different combinations of vendor equipment in a remarkably short time. In addition to Evertz, companies bringing equipment to the Plugfest included Calian Advanced Technologies, Keysight, Kratos, ST Engineering iDirect, Wavestream and Welkin Sciences.

“With this first Plugfest, the DIFI standard takes a leap from the meeting rooms where working groups gathered to the marketplace where technology evolves. DIFI will keep working to create an open and transparent standard, developed by users, operators and vendors working together, that enables true interoperability among all vendor’s communications technology. It will reduce the total cost of ownership and boost network and terminal agility, performance and resilience. Longer-term, it will open the door to new markets, greater integration with terrestrial services and a truly software-defined future for the industry.”

About DIFI

The mission of the Digital Intermediate Frequency Interoperability (DIFI) Consortium is to enable the digital transformation of space, satellite, and related industries by providing a simple, open, interoperable Digital IF/RF standard that replaces the natural interoperability of analog IF signals and helps prevent vendor lock-in. Today, ground segment relies on coaxial cable to transport RF at intermediate frequencies, such as L-Band, between antennas and modems and through multiple analog devices. Analog IF systems, with their inflexible chain of hardware, are difficult to scale and complex to operate. They are struggling to handle today’s capacity demands and cannot scale up to meet the needs of tomorrow.

The industry needs an open and transparent standard, developed and adopted not by vendors alone but by users, operators and vendors working together.  A standard that meets the broadest range of needs without becoming too complex and costly to implement.  A standard that reduces the total cost of ownership and boosts network and terminal agility, performance and resilience, enabling ground segment to seamlessly adapt to rapidly changing space-layer payloads, orbits and constellations.



Joni Sterlacci, Sr. Program Manager,