Often when a business is looking for a commercial intercom, what they really need is a telephone system along with an external paging system. The telephone system allows employees to either call specific areas of the building, or with an external paging amplifier and speakers, they can page the entire building. A door phone can be added to the telephone system to enable visitors to an external door of the building to press a button to call someone inside, and that inside person could press a button to unlock the door.
However, there are times where a telephone system is not what is wanted. Telephone systems are expensive and the labor required to run the wires throughout the building is just as expensive.
If all that is wanted is the door phone application, then you can get intercoms that have a single outdoor monitor along with a desktop or wall mounted indoor station. Then there is only one wire to run between the door and the inside station. Or you can also choose wireless intercoms for this application.
Sometimes there are just a few areas of the business where some form of communication is needed and there is no desire to run wires to them. That's where wireless commercial intercoms are needed.
One problem with wireless intercoms in many commercial intercom applications is that the environment is more challenging for the wireless equipment. In manufacturing companies there is a lot of equipment that may produce interference. The building construction often consists of metal framed walls and more electrical wiring to handle office equipment. Many commercial buildings are made of concrete walls and floors. These conditions will greatly reduce the range of a wireless intercom.
So when you look for wireless commercial intercom systems you want to make sure a system has a much longer range than you actually need. The longer range the intercom system has, the more power it has to overcome the obstacles in a commercial environment.
These next sections review some of your options for a wireless intercom system.
Intercoms in the 900 MHz frequency really have limited use in commercial applications. The range is usually too limited.
If your building is not large or made out of concrete and metal, then a 900MHz intercom may work perfectly OK for you. Many small businesses use them.
Yet another wireless intercom system is not so much of a system from one manufacturer as it is a compilation of wireless intercoms and two-way radios. This MURS system is based on compatible products in the MURS radio frequency. As talked about above, MURS stands for Multi-Use Radio Service and is a two-way radio service consisting of five frequencies in the VHF (Very High Frequency) spectrum. Unlike most frequencies in the VHF range, MURS does not require an FCC license to operate.
Even though there are only 5 channels, each channel can choose between one of 38 ?quiet codes? or sub-channels to keep you from hearing conversations of other users on that channel. You will only hear conversations from radios set to the same channel and quiet code as your radio. In most areas the MURS frequencies are very lightly used so you won't find a lot of competition for the airwaves.
The biggest benefit of MURS is the range it offers. Some manufacturers claim a range of four miles. Of course this range is a line of sight with no obstructions between intercoms. Range can even be increased with these intercoms by adding an external high-gain antenna on top of your business, or even car if you use a unit there.
What's nice about MURS is that you can get handheld two-way radios, commercial-duty base station and outdoor intercoms/callboxes, and even motion detectors that transmit a verbal alert message to other MURS devices. For business, industrial, or commercial applications a MURS system excels since it can overcome a lot of interference and obstacles these applications present.
If you need a wireless PA (public address) system, there is a wireless PA device that works with all the MURS radios. For retail business that service customers directly, there is even a wireless MURS device that enables customers to press a button and call for assistance via a transmitted recorded message.
Since any manufacturer can create a MURS wireless device, choosing a MURS system keeps you from being locked in to whatever products a particular manufacturer chooses to offer.
If you are willing to get a license for your radio, then you can use either the UHF or VHF business bands. You can get most of the same devices as you can in the MURS range above.
When you need a way for clients, students, employees, or anyone else to communicate with you from distant areas of your campus or property, a callbox or call box is one way to do it. A call box is a box made of metal or fiberglass that contains electronic circuitry that enables someone to press a button or pick up a handset and call a central location for assistance. Some callboxes also allow calling a portable radio so that assistance can be mobile.
There are two main types of callbox units available, wired and wireless. A wired callbox involves running a cable to it from the central location. This section is about the other kind, the wireless call box .
The benefit of a wireless callbox is that you save money by not having to do trenching and running expensive cable to the unit. You also don't have to pay any air-time or telephone service fees with these wireless systems. As mentioned, another benefit is that since the unit is wireless, people monitoring the units can carry handheld radios that communicate with the callbox. That allows your monitoring people to be mobile.
The range of these units is several miles, which can be extended by adding an external antenna. Some units can use radio repeaters to extend this range even more.
If you have existing two-way business radios, you'll want a system that can integrate with them. Some callboxes can be programmed to be compatible with virtually any brand of VHF or UHF business band radio.
You can get call boxes that require an FCC license, or you can get units that are certified for use on special FCC License-Free MURS Business Frequencies. If you choose a licensed version, the license is usually not too difficult or expensive to obtain.
One problem you may have in placing a call box is the lack of available power. You'll want to choose a system that lets you use battery or AC power. You can also get units that have optional solar power so that they can run for several days on a single day of sunshine.
If you need to remotely control gates, magnetic door locks, or barrier arms from your portable 2-way radio or desktop base station intercom, then select a unit that has this capability. With this ability you can let someone in a gate or door when they call you. There are units that also let you turn on a strobe light at the callbox location to help draw attention to it.
Another useful feature is the ability for call boxes to store a voice message that is played when someone presses its button. This could be a message that gives the caller specific instructions on what to do. These units can also send a second and different voice message alert to the monitoring central location or portable radios. This message could give the callboxes location or it could be an emergency message of some type.
If you have several callboxes in use and you need to know the location of the unit calling in, then you can get a call box that transmits a unique numeric identifier to a radio that has the ability to decode this identifier. This is like having a telephone with Caller ID capability.
By adding a motion detector or some other detection device, you can be alerted when that detection device is activated. Some callboxes will send either a tone alert or a custom voice alert when the detection sensor status changes. If this voice message is not immediately answered, the alert message is resent multiple times.
If you are running your system on battery power, you need a unit that has battery conservation mode. In this mode, only the absolute necessities for operation are powered, and the unit can not accept calls to it; it can only make calls. You can attach an external sensor to automatically put the unit into full power mode when someone is detected near the box. This will allow you to make a call to it.
Other useful features:
- If you want to listen to what's happening around the call box, then you'll need a unit that can be paged so you can use the callbox microphone to monitor the sound around it.
- A low battery alert or external power fail tone is sent to the monitoring portable radio or base intercom.
- A paging feature allows selective calling of individual boxes or a group of callboxes simultaneously.
- The busy channel feature prevents someone from transmitting if someone else is using the radio channel.
- Wireless callboxes have fast installation since no wiring is required.
- Entry keypad with built-in relay lets people enter a code at the call box to open a gate or door. Remote opening of the gate by monitoring personnel can still happen also.
These callboxes are being used for applications like parking lots, college campuses, airports, hospitals, construction sites, manufacturing facilities, resorts, hotels, farms, warehouses, delivery docks, campgrounds, gated facilities, or anywhere people may need assistance. So by using call boxes, you can put clear wireless voice communication anywhere you need it, quickly, without expensive trenching and monthly air-time fees.
Author: David Onslow