Every call on a PRI span is sent with the called number in the setup message. This means you can determine whether to use a number as a pilot number or as a DID number. Pilot numbers are a means of routing a company’s primary published phone number differently from a DID. Each ESI Communications Server has a different capacity for pilot entries, each with its own answer ring assignment; see “Translation tables” in “System capacities” (page B.1). This is important, because the dynamic channel allocation prevents you from routing based on channel. Pilot numbers can be routed to an ID branch, department, extension or mailbox. This varies from DIDs in that, when a DID number is routed to an extension, it is considered answered and follows the busy/ no-answer routing of the extension; but, with pilot numbers, the call will be routed to the extensions for live answer for the designated number of rings, then can be routed to an ID branch in the event of busy/no-answer. If the PRI span is used for outgoing calls, pilot table entry 1 is used for outgoing Caller ID, as well. Because of this, pilot number entry 1 should always be programmed with 10 digits.