Dear Linda: For all intents and purposes, SPDIF protocol and AES protocol are compatible. It’s the same data and can be passed from one machine to another. There is a pro and a consumer bit, but most devices these days ignore the incompatible bits. Years ago, DAT machines gave people trouble but those are gone and most DAWs and samplers will ignore the bits. So, SPDIF and AES protocol are pretty much interchangeable.
Then there’s the voltage, impedance, and balancing, unbalancing.
A simple Neutrik or Canare transformer does the job. I think that Sescom has one, too. Google 110 ohm to 75 ohm AES transformer and see if you find what you need.
Here’s an example:
A BNC to RCA adapter or cable finishes the job.