Add FAQ item re: Serial Monitor

Author: per1234

Diff for: docs/FAQ.md

@@ -17,9 +17,20 @@ Additional board options have to be separated by commas (instead of colon):
 
 `$ arduino-cli compile --fqbn "esp8266:esp8266:generic:xtal=160,baud=57600" TestSketch`
 
+## Where is the Serial Monitor?
+
+Being this a command line tool we believe it's up to the user to choose their preferred way of interacting with the
+serial connection. If we were to integrate it into the CLI we'd end up putting a tool inside a tool, and this would be
+something that we're trying to avoid.
+
+There are many excellent serial terminals to chose from. On Linux or macOS, you may already have [screen][screen]
+installed. On Windows, a good choice for command line usage is Plink, included with [PuTTY][putty].
+
 ## Additional assistance
 
 If your question wasn't answered, feel free to ask on [Arduino CLI's forum board][1].
 
 [0]: platform-specification.md
 [1]: https://forum.arduino.cc/index.php?board=145.0
+[screen]: https://www.gnu.org/software/screen/manual/screen.html
+[putty]: https://www.chiark.greenend.org.uk/~sgtatham/putty/