Scan the bar gun issue

Op cash register systems, to buy a gun scanning is not sweep, and also flash a red light, sound,
is also set to ask
If you want to set up how it is going to set up a
Thank you for your advice With the help

scanning gun fight after the call, as each of the settings are not the same as Data is not the computer com port Is not working.Scanning machine is not set, and it's the same keyboard.Try the distance from the bar code, can adjust the distance to see a sweep, for more than a few bar code scanning.If not, there may be a bad gun.