Hi, I found an old phone that was being thrown away at a local business and I took it home. I was told the phone was in working condition and that I would need a KSU to get it up and running. However, I am not sure which KSU to get. There is no model number or brand name however I have found a website which has a phone picture that is exactly like the one I have. I would be very grateful for any information on this phone as I could not find anything. The website is https://seriss.com/people/erco/1a2/ and the phone is the Model 2830. Any help would be greatly appreciated. Thanks so much.