A CFC that accepts text input and returns text responses can easily be made accessible via Telnet. This is what you'll need to do:
1) Make a copy of /cfusionmx7/gateway/config/socket.cfg (name it telnet.cfg perhaps), and then edit the copy and change the port: port=23.
2) Create a new gateway instance of type "TCP/IP Socket", give it a unique name, point it at the telnet.cfg config file, and at your CFC file.
3) Start the new gateway instance.
4) Use a Telnet client to connect to your ColdFusion server (specify DNS name or IP address).
That should do it.