There is a flood of low cost video doorbell systems on the market that are built for light duty use, but for commercial environments you'll need something more durable like a commercial video intercom system. Commercial environments like offices, industrial plants, warehouses, manufacturing facilities are more likely to see lots more people using them so you need something that will hold up to extra abuse. They may also be used at security gates where they are exposed to weather extremes.
There are both wired and wireless systems available. One thing to note is that with video intercoms there are distance limitations on how far the intercom can be from the monitor. For wired systems the distance is around 330 feet. Surprisingly wireless can be further with the right system.
With a Wi-Fi video intercom system the distance limitation is only determinant on whether you can get a strong WiFi signal where you want the camera intercom. There are extenders that can reach ranges of miles under ideal conditions. These camera intercoms communicate with an app on a smartphone or tablet PC so that's what you use to view visitors. A wall mounted touch screen monitor is also available.
You can also get wireless video intercoms that use cell phone technology so as long as you have a strong cell phone signal where you want to put the camera intercom then it doesn't matter how far away the monitor is. These units communicate with an app on a smartphone so you can view visitors.
To see systems available click here: video intercoms
Give us a call at 888-298-9489 for assistance in choosing a system for you.