Hello! I haven't been using this program for a long time and in the moment I can't install it on my computer (until Sunday I'm not at my home) - but I'll try to help you. This simulator is not a precise simulator of any concrete radiotelex hardware - it just simulates those functions which are common in radiotelexes. It is also 13 years old. It may be useful for you or not. If it is useful - great! General idea: If you want to use it to simulate communication between two radiotelexes (for instance using FEC) you will need one server and two clients. The server is program called "centrala.exe" - do you have it installed? The client is the radiotelex simulator. If everything is configured well and the server is running, the clients will contact the server and they will be able to talk with each other through this server. Details: when you start the simulator for the first time it asks you some questions. Then it stores your answers in configuration file which is in c:\telex directory. If you want to change yours answers you can edit this configuration file or delete the c:\telex directory and then restart the simulator. The questions means: "numer selcall" - it means "your selcall number". Here you can provide any number. When you install radiotelex simulator on two (or more) comupters and you will communicate between them, each radiotelex simulator should use unique number. "znamiennik" - I'm not sure how it is in English, I think it is a "callsign" or something similar. Generally, it should be any name, also unique for each radiotelex simulator. "numer IP centrali" - it means "server's IP address". Here you should type the IP address of the computer on which you run the server (the "centrala.exe" program). "automatycznie łącz z centralą przy uruchomieniu programu" - it means "automatically connect with server when the program starts". You should switch it on, so each time you start the radiotelex simulator, it connects to the server (and you don't have to connect it manually). Then, in order to simulate FEC communication, you have to: Start "centrala.exe" on one computer. Start the first radiotelex simulator on some computer. It can be (but doesn't have to be) the same computer on which "centrala.exe" is running. Go to "frequencies" menu. Set some Rx (receiving) and Tx (transmission) frequency. Remember them. Start the second radiotelex simulator on some computer. I guess it could be the same computer on which "centrala.exe" and the first simulator runs, but I usually have been running it on some other computer. Go to the "applications - editor" menu. Write the text to be sent. Go to the "applications - radiotelex" menu. Go to "frequencies" menu. As Tx (transmission) frequency set the Rx frequency of the first simulator. Go to the "connect - FEC" menu. This should send the text to the first radiotelex simulator. Please, write me if it worked for you!