Phone info

Numbers

ANACS

When you call an ANAC you get an ARU. It will say:

"The ARU ID is
your line number is {trunk number},
the DNIS is {DNIS number}, the ANI is {flex ANI}.

Definitions

ANI
Automatic Number Identification -- a service feature that transmits a directory number or Billing Telephone Number (BTN) to wherever you are calling. Unlike Caller ID, cannot be blocked. (Also, Caller ID is not necessarily the BTN.)
ANI fail
When no ANI is sent. (II and area code may be sent, but without the rest of the ANI, it's an ANI fail.)
ANAC
Automatic Number Announcement Circuit -- a circuit that announces what ANI you are calling from.
ARU
Audio response unit -- the circuit which announces your ANI.
BTN
Billing Telephone Number -- a phone number that charges are to be billed to (not necessarily the one you are calling from).
DNIS
Dialed Number Identification Service -- tells you which number you called.
Flex ANI
Prepends two "II" (identification indicator) digits to the ANI. Some examples:
op diverting
Having the local operator dial the destination number for you, used to intentionally cause an ANI fail.
PANI
Psuedo ANI -- a unique non-diallable number used to route cellular calls. 911 operators use it to locate the cell site and sector you are calling from.