<p>I have a generic printer with no support documentation. </p>

<p>How do I determine what firmware is in use so that I can research how to make the print run?</p>

Send
```
M115
```
to the printer. This command is
Request the Firmware Version and Capabilities of the current microcontroller.
Response example:
ok PROTOCOL_VERSION:0.1 FIRMWARE_NAME:FiveD FIRMWARE_URL:http%3A//reprap.org MACHINE_TYPE:Mendel EXTRUDER_COUNT:1
For more info see here,
RepRapWiki- G-code - M115: Get Firmware Version and Capabilities
.
Of course, this isn't guaranteed to tell the truth, just whatever your generic clone firmware had in its source code.