Hello,
Thank you for your message.
The backslash key on this device is not a standard key in the keyboard layout. However, you can get the backslash key by pressing this key combination: Control, Alt and Hash key.
Please see the photograph below/attached which demonstrates the keys to press. You can press on the keys one at a time, but must end with them all held down together achieve the backslash symbol.
We hope that this helps. Please let us know if you need any more assistance.
Kind Regards,
