ESP8266 Echos AT but will not Respond with OK

(click here to see index of all ESP8266 posts)

I’ve been playing with the ESP8266 a little for the past week and will shortly start posting some stuff, but the first head scratcher I ran across which I still have not seen documentation on is this:

You get the ESP8266 connected to your PC via an FTDI cable. When you type AT, it properly echos ‘AT’ back at you. But when you press ENTER (<CR>) you do not get an OK response.

Unlike anything else I’ve used in the past that uses the AT command set, control-M a.k.a. ENTER a.k.a carriage return (<CR>) is not enough. You must then press control-j (line feed).

So if you type AT<control-m><control-j> you should get an OK. At least I did.

In my terminal emulator of choice (an ancient copy of WRQ’s Reflections), there is a mode called AUTO LF. If I turn that on, then any time I press control-m, the sequence <control-m><control-j> is sent, and that solves the problem for me.


I took a look at PUTTY, the only other serial port terminal emulator I ever use and while it has an option that seems that it would do an auto lf, it does not work for me.


So with PUTTY, I still have to type control-m control-j to terminate each AT command.



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2 Responses to ESP8266 Echos AT but will not Respond with OK

  1. Pingback: Basic ESP8266 Setup and Operation | Big Dan the Blogging Man

  2. Richard says:

    You found the trick too! Took me over a week to figure it out. I was complaining to the seller that his product would not respond to AT commands😦

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