The TelNet 3270 communication protocol (TN3270) is a subset of the TelNet protocol, that uses the IBM 3270 terminal command set instead of the normal DEC VT100 terminal command set. An example of a Server using this terminal would be an Internet connected IBM System/360 mainframe. Below are contacts for TN3270 servers on which public access is freely given.*
[IANA Port assignment = 23]
* Please note that anonymous logins are almost never used on systems using this protocol subset, so the server administrator must first be contacted to assign a unique user login.