[dba-SQLServer]Ideas comments HELP

Heres the idea

We have a hand held scanner which contains a table
We link Said scanner to SQL Server
If the table data on scanner is different in any way to the data in the same
table on SQL Server we replace SQL Server table with the scanner table or
just the different rows.

Question

1. Whats the best way to do this?
2. Can this be done without pulling the table of the scanner?
3. Is there anyway we could create checksums for a table and compare them?

Any one any clever ideas. Speed is a real issue here.

Martin