Bar Code Implementation Tips And Guidance

I have an intranet site that controls equipments flow for three companies.
Recently one of the key users of one company asked me if the manual input they use to track the equipments and use the functions of the system could be replaced for a bar code scan...

So the basic idea is to add an icon beside the manual input that locate the equipment, as an option to use bar code scan pistol instead of typing.

There is some example of this kind of implementation, if its even possible?
Could you show me the way, like choosing the right bar code standard, how to control scan`s API from asp, etc?