FTP puts data and commands on the same socket. This is perfectly doable in NCP.

bbanyc · on Oct 25, 2019

> FTP puts data and commands on the same socket.

Not on TCP it doesn't. And some of the Arpanet FTP RFCs refer to separate connections as well, e.g. for the MAIL and MLFL commands which send email over the command and data connections, respectively. (SMTP didn't exist yet so mail was sent over FTP.)