Coax adapter

> Can this [...] be used to connect to the coax to connect to this [...]

   "the coax"?  _Which_ "the coax", from _where_?

   What, exactly, are you trying to do?  If you're asking whether a $5
thimble-sized gizmo can replace a cable-TV modem, then the answer is no.

   I can't (yet) see your (second) picture. In-line images must be
approved by a moderator before others can see them.  The time required
varies.  Attachments have no such limitation.  Of course, attachments
have their own one-per-message limitation.