Transferring a file with ymodem over TCP network

I have a device (RELAY) I am able to telnet into using its IP address from an linux machine (CLIENT) and I'd like to copy a file from the RELAY to the CLIENT. I have very limited privileges on RELAY, but I can view a list of files on it with file dir, and then I should be able to download a file from it using YModem, per the manufacturer, who instructed that the command to send the file is

file read filename.ext

After typing that it displays

> #000 Ready to send file

but I'm not sure how to set up a method to receive the file on CLIENT I have full access to. I've read in this post to receive using minicom, but that appears to be for a serial connection and I'm doing this over a TCP network. I've tried with sz as well and tried to use the --tcp options, but again am not sure if it's simply me not understanding which options to use or if this method isn't correct. What are possible methods for me to connect to RELAY from CLIENT and tell it I'm ready to receive the file? (edit) I had a request to edit this question about why it's different than the one I linked to, and the reason it's different is that for my application I'm using telnet over TCP and the previously linked discussion is using a serial connection.