user21244: I'm unable to communicate with my nodemcu ESP8266 module using the AT commands. The module does not return 'ready'  on the serial monitor and entering AT commands has no effect at all. I am able to upload programs onto the module and even receive messages onto the serial monitor. But not for the AT commands.  Please help.... 

user4143: AT commands require the installation of firmware that responds to AT commands.
A plain ESP module normally comes with that firmware installed. A nodemcu doesn't. A nodemcu comes with Lua installed instead.

user313: The bare chip knows nothing, just as an Arduino would. The AT+ command set is provided by an interpreter running on the 8266 processor. The AI Thinker modules and others, come with that interpreter already loaded. Your module does not have it installed. And any time you load a program into it, the previous one is over-written. 
You can find the AT+ interpreter available for download and upload it to the module, after which it will be able to execute AT+... commands.

21244: <p>I'm unable to communicate with my nodemcu ESP8266 module using the AT commands. The module does not return 'ready'  on the serial monitor and entering AT commands has no effect at all. I am able to upload programs onto the module and even receive messages onto the serial monitor. But not for the AT commands.  Please help.... </p>
 4143: <p>AT commands require the installation of firmware that responds to AT commands.</p>

<p>A plain ESP module normally comes with that firmware installed. A nodemcu doesn't. A nodemcu comes with Lua installed instead.</p>
 313: <p>The bare chip knows nothing, just as an Arduino would. The AT+ command set is provided by an interpreter running on the 8266 processor. The AI Thinker modules and others, come with that interpreter already loaded. Your module does not have it installed. And any time you load a program into it, the previous one is over-written. </p>

<p>You can find the AT+ interpreter available for download and upload it to the module, after which it will be able to execute AT+... commands.</p>
