The basics of private branch exchange (PBX) are clear to anyone who has ever called a doctor's office: You get a receptionist, a recording, or a chance to search for your contact by name, and perhaps leave a voicemail.While not complex nor tremendously expensive, a virtual PBX system is hardware and virtual PBX software that must be bought, installed, serviced and, eventually, replaced. If your office is small (under 100) or has a load of telecommuters, part-timers or just busy, mobile sales people, a virtual PBX service might be a good choice. Lose the hardware, and only rent the virtual PBX software side online, over the Web using VoIP PBX or hosted PBX.In guide, the basics of virtual PBX systems are covered, including:1. Basic virtual PBX service2. Comparing virtual PBX with standard PBX service3. Buying hosted PBX and VoIP PBX4. Small business PBX options Start off slow with basic virtual PBX service features The world of telecom acronyms can be pretty jarring. If what you want is a receptionist and voicemail, small business PBX can be cheaper and easier to buy than fully-blown virtual PBX system or hosted PBX. Complete virtual PBX systems are plenty and plenty competitive If you've priced a fully blown small business PBX system, take your bid and stack it up against virtual PBX software for a good comparison. virtual PBX service.Hosted PBX can bring a load of advantages besides cost Because it relies on your Internet connection to work, hosted PBX can put your phone calls into an integrated, always-on world. Track people down, have clients find you, assign numbers on the fly. The sky is (nearly) the limit, and even big vendors have small business PBX packages. Cut costs dramatically using VoIP PBX Voice over Internet Protocol (VoIP) uses the Internet to route your business calls, a very cheap alternative to traditional phone lines for small business PBX. Given that the calls are already coming through a server, it's possible to add virtual PBX features over the Web using virtual PBX software. Small business PBX for the very small business Some providers have structured their offerings around not just small business PBX but even single users. This flavor of small business PBX is good for independent contractors, real estate professionals and consultants, these plans have simplified Web interfaces, much like VoIP PBX, charge for a set number minutes, much like cell phone plans. Virtual PBX service, once operational, can make it easier still to use popular customer relationship manager (CRM) software. If you have bought or are looking at CRM systems in addition to your virtual PBX software, ask your vendor about small business PBX integration. Hosted PBX systems increasingly can see phone numbers for what they are: numbers. If half your sales force is on cellular phones, they can be included in the small business PBX directory. Some allow programming that rings office phones during business hours, then cellular phones after hours. Avoid signing contracts. Most virtual PBX systems will let you go month to month on a small business PBX plan (although some may charge more for that) on the expectation that either comfort, or sloth, will keep you on board. Try before you buy, in any case.