1. connect to a serial device
2. emulate a terminal (VT100, etc)
Now if you want to remotely access that serial port, and you can use a program to convert the serial data stream to TCP data stream (ser2net/remserial on Linux, com2tcp on Windows). The only thing is that you still need a "terminal emulator" to get full capability (vi, etc) from that console.
One way to do it to use "putty", and use "raw tcp" and make sure you set "local echo" to "off", and "local line editing" to off on the "Terminal" tab of the Settings.
Another way is to run a local tcp-to-com kind of program. On linux, you can use remserial to create a virtual com port, and on Windows I think you can use com2tcp/com0com to do it. But I think using putty to access it directly is easier.