Hi,
DevTest does not include a TCP request sending specialized step for test cases(.tst. files), but you can use "Execute Script(JSR-223) step" to write a script for realizing your requirement.
In "Execute Script(JSR-223) step", you can select from:
•Applescript (for OS X)
•Beanshell
•Freemarker
•Groovy
•JavaScript
•Velocity
for scripting.
Thank you,