A good quality barcode scanner is very useful for quick and easy event check-in with barcoded invitations.
The scanners that are typically found in a mission's consular section and/or mailroom tend to work well, can be borrowed in order to avoid purchase cost, and are already fully approved for use on OpenNet by the ITCCB in Washington.
One specific model found in many mission mailrooms is the Honeywell Granit 1910i. It can be purchased via CDWG.com.
Technically, most any 2d scanner that shows up as a keyboard interface would work with eContact.
We highly recommend testing any barcode scanner well in advance, with a mock/sample event and mock/sample invitations, before using any scanner for a real event.