DID stands for Direct Inward Dialing. This is a special service that most local phone companies can supply.They install a special telephone line that they call a DID "Trunk" (that's phone talk for a wire that carries phone signals). Then they assign a block of telephone numbers to that "Trunk". Now, when someone calls any one of those numbers, the DID trunk "rings" (well not really, but I want to keep this simple for a while). At the same time, the phone company passes the last four digits of the number that the caller dialed along the trunk. The VBX 400 DID card figures out what number was passed, answers the call and immediately moves the caller to the tree object in the answering application that matches the 4 digit number. OK, OK that's still not clear! Now let's try it again. For example, the phone company might assign the 100 phone numbers from 769-5200 to 769-5299 to the DID trunk. You build a voice mail application that contains 100 mailboxes, numbered 5200 to 5299 and schedule that application to run on the new line. Now, someone calls 769-5240. When the DID trunk rings, the caller is immediately moved to mailbox 5240, without stopping at the System Greeting or Initial Prompt. Box 5240 might say something like "Thank you for calling Acme Brick Company. Please leave us a message." Thus, a mailbox appears to answer the phone. Now if the next call was dialed as 769-5210, then mailbox 5210 would answer the call. Therefore, to reach each mailbox, the callers must dial a different phone number for each box in the application.How does that make you money? You can now give each of your voice mail customers a private phone number to reach their mailbox. Your customers can forward their own phone to their private DID number. When someone calls that customer's phone, your system answers as if were at the customers location and answers with the customers own greeting instead of a menu. You could even offer more than a simple mailbox. If the object were a Prompt, you could offer sub-mailboxes and if the object were a Control Point, you could chain to any application and offer any type of service that you could imagine. Actually, any of your inbound type applications can use the DID lines if you have designed them to have the correct object ID's. How do you get started? First, you need to do some research and some math. The VBX 400 DID card is only available as a 4 line card and costs about the same as a regular 4 line card. Now call your phone company and ask them if they can install DID trunks at your location. Tell them you need "Wink Start with 4 DTMF digits" (Don't you just love this phone talk!) They will tell you how much it costs. Expect to pay about $75 per month or so for each trunk line and then from 25 to 40 cents per month for each phone number assigned to the trunks. You will likely be asked to pay an installation charge of around $200. These are my best guesses, your phone company may charge more or less. Since a trunk can only carry one conversation at a time (just like an ordinary line), you may need to consider 2 or more trunks. If so, the trunks are usually configured as a "Hunt Group" so that you can run the same application an all trunk lines and have multiple calls handled at the same time. Then talk to your voice mail customers and prospects and find out if they would like this type of service (you can charge more too). Now get out your sharpest pencil and figure out if you can increase your business enough to cover the costs of all this new stuff and make a profit. If the numbers work, then call Customer Service and order the "DID Option". Is that all there is to it? Not quite. DID lines are special. The "premises equipment" (that's phone talk for your computer) must supply power to the DID trunks. You will also need an external power supply as part of the DID setup. Since the whole thing works by manipulating voltages from this power supply, you must plan on leaving the power supply and computer on for 24 hours a day, 7 days a week. You should also connect the computer and power supply to a UPS (battery backup). The phone company will disable your DID trunks if power is removed from the line for any extended period of time and they may charge you to reactivate the service, so this is important.In addition, the DID option does not support outbound calls, only inbound calls. Therefore, these lines will not support "Call Transfer". However, the manual will tell you how to set up message forwarding for voice mail boxes, using one of your regular lines.The DID option is not an instant solution to a problem It is a tool that has the POTENTIAL to increase your income if you market these new services wisely. It does, however, level the playing field for you and give you a competitive edge. You would probably be able to offer more features in your voice mail and audio text services than even your own phone company or other providers in your area and command a premium price for those services.