Hey Jerry, That's an unusual audio panel, I'm thinking that your best bet for getting some money out of it is to try selling it on eBay. Sometimes the rarity of something like can be quite appealing to eBay buyers. If you go that route, be sure to include information about the unit being still available at $4K, I'll bet there are some pilots out there that would be very interested in having an audio panel that has these unusual capabilities.