I’m trying to use Particle Photon as a replacement of a USB card reader connected to a printer, the reader I’m replacing works as a keyboard emulator, when connected a computer both the Photon and the Card Reader behave the same, but when connected to the printer the Photon is recognized and registered as a card reader but the key strokes are not recognized by the printer.
I used USB analyzer to compare the packets sent from both devices as well as a USB Keyboard, I notice the Photon sends each key as 9 bytes, while the reader and my keyboard send 8 bytes.
Here is an example of KEY_1 packet:
02 00 00 1E 00 00 00 00 00 from Photon
00 00 1E 00 00 00 00 00 from Keyboard & Card Reader
It’s the same packet but photons always adds 02 at the start!
Is there any way to change that?