When you use telnet to test a service in this way, you’re not talking with a telnet daemon, but only using the telnet command to make the connection for you to connect to the service if your choice.

Although I just use telnet for basic Web server troubleshooting, telnet ends up being my preferred tool for e-mail troubleshooting, mostly because it's so simple to send a complete e-mail with only a ...

But when I execute telnet, it just dumps me back to the command prompt, which would seem to indicate that the telnet application is opening up its own interface window (on the server) that I, of ...

Note that being able to talk to something with plain text commands over telnet is a security red flag. It looks like at least some Crestron devices support securing CTP traffic with SSL.