Avision AV50F (FF-0803S) - Manual (Page 12)

Installation Steps
Align the scan module to the document feeder and insert it on
the document feeder. If it has been inserted successfully, a
snap in sound could be heard.
The scan
module
Important:
Before installing the scan module to the auto document feeder,
please first remove the protection cushion both inside and
outside the scan module.
2-3