It's important to note that not all unified messaging systems perform the same functions. All web and software-based systems range in pricing and function.

And some of the more expensive services and systems will allow you extra features and goodies as an add-on, while some provide only the basic service.

However, that's not always easy to tell from brochures-you'll want to check out exactly what a program can or cannot do by testing it yourself through demos.

The bottom line: If a specific feature is critical to your business, make sure it currently exists as a standard feature or an add-on with the service or system you are considering. Promises of future implementation isn't enough to warrant your purchase.

You may want to keep in mind some differences we have uncovered:

Email options can be limited

• Not all services are ready-to-go; some plans require subscribing to certain email providers if you want email messages to be included in your unified inbox.

• Not every web-based service uses text-to-speech technology, so you won't always have the option to listen to your email or faxes over the phone.

• Some software-based systems don't allow remote access to email, so you can't access email from the road.

Commitment levels and testing opportunities can vary
Most web-based services are paid on a monthly basis, but make sure before signing up that you can safely cancel your service without penalties at any time. (Many offer the first month free.)

For software-based systems, ask them about demos. Some offer downloadable demos (they'll give details on the procedure) that will last about a month or so.

Testing systems and services can give you insight into the typical user experience. For example, some unified messaging systems require the user to open one window to read faxes and email and another window for voice mail, which some users may find unwieldy.