The simplest scenario is a home office or a teleworker operating at home. If usage is very light and you don't need a special business listing, the residential landline or personal cell phone may be enough. If more that one person needs to use the line, you simply add extensions or get a wireless phone system that includes one or more extra phones.
But what if usage is heavy or you want a special line just for that business? One solution is to add a second phone line with its own telephone, answering machine, and FAX machine. Going a step further, install two-line phones so you can select which line you want to answer from anywhere in the house.
This is the start of what's called a key telephone system or key telephone unit. Every phone has all of the telephone lines available. A light next to the line switch tells you whether that line is in use or not. You answer the line that's ringing because its light is blinking, or select a line that is not in use to make your call. If you choose a line that is in use, you have an instant party line conference going.
Many small and even medium sized offices have key telephone systems as an alternative to giving everyone their very own outside line. If your business doesn't require everyone to be on the phone all the time, two, four or six phone lines might be all you really need to service the whole office, factory or store.
The next step up is a PBX or private branch exchange. It's like having your own little phone office. Phones connected to a PBX system do not have phone line buttons. Instead you dial a number such as 9 to get an outside line. The PBX system assigns you next available line when you need it. If you are going to call someone in the same building, you just dial their extension. The call is connected through the PBX and doesn't even use a public phone line.
You can add phone lines to the PBX as your need grows. Once you get up to a dozen or so outside lines, it is often less expensive to consolidate all those individual local lines into a single digital T1 or PRI line. T1 gives you up to 24 phone lines and PRI gives you up to 23 plus caller ID information. If you need more than 23 or 24 lines you just add another interface card to your PBX and install a second T1 or PRI line.
A competing technology is VoIP or Voice Over Internet Protocol. In the home office example, a VoIP phone could be installed instead of a second landline. The VoIP phone or VoIP adaptor connects to the home's router and shares the broadband service with one or more computers. Some VoIP adaptors let you add two phones or one phone and one FAX machine, each with their own phone numbers. If you already have broadband, you'll probably find that using VoIP for a second phone is cheaper than installing a second landline.
With VoIP the concept of a phone "line" gets a bit fuzzy. VoIP converts telephone voice and signaling into data packets that are carried on computer networks or broadband Internet. If you need to add more phones, you increase the capacity of your network instead of adding more wires from the phone company. From an electrical standpoint it seems like one big party line. Unlike the party lines of old, however, every VoIP conversation is separate and private. You don't have to worry about your neighbor picking up the phone and listening in to your conversation ...like many of our parents and grandparents did.
For PBX based phone systems, T1 Rex will help you find the best prices for your T1 or PRI line service.
