A local station has a telephone hybrid labeled Comrex Access with a Rack Control Surface. That's the only model information we can find. No one left at the station knows how to use it, so I'm trying to identify the model so that I can download the manual. I'm sure it's a common model, but it's at least several years old. Is that enough information to identify the unit? I've been through the Comrex website, and I cannot find a picture of the control module to help identify it.