Abandoned Call A call into an ACD or IVR system where the caller
hangs up before an agent answers.
ACD (Automated Call Distribution)
Device that automatically answers all incoming calls, sends the calls to the first
available agent, or, if all agents are busy, plays a recorded message and
places the call into a queue until an agent becomes available.
Analog Phone Line
Traditional telephone service (non-T1) whereby phone lines are delivered
to the customer via copper wires. Each phone line requires two
wires, and this service is typically associated with residential service
or businesses that have fewer than 6 phone lines.
ANI (Automatic Number Identification)
The called-from phone number that is propagated through the public telephone network when a call is placed.
ARS (Automatic Route Selection)
Ability for a telephony system to route outbound calls based upon a
pre-determined routing table which selects the most economical route.
Sometimes referred to as LCR or Least Cost Routing.
ATA (Analog Telephone Adapter)
Device placed between an internet connection and a standard analog
phone which turns a traditional telephony device into an IP device.
Allows the user to utilize a traditional analog phone to place calls via VoIP over an internet connection.
Bell Operating Company (BOC)
Refers to any of the 22 original companies (or their successors) created when AT&T
was broken up in 1983. The companies had been subsidiaries of AT&T and were called the Bell System. Each was
given the right to provide local telephone service in a given geographic area.
The purpose of the breakup was to create competition at both the local and long-distance service levels.
Feature provided by the local service provider that can be added to a
phone line or hunt group whereby an incoming call is forwarded to an
alternate number or voice mail when all lines are busy.
A 60-minute period during which the average volume of telecommunications traffic is at its maximum.
The called from name and number that is transmitted and displayed over
PSTN lines. The caller has the ability to block delivery of this
information by dialing 67 before dialing the destination number.
Telecommunications provider which owns or operates a long distance telephony network within the PSTN.
CAS (Channel Access Signaling)
Traditional type of call-control used on T1 lines where the on and
off-hook signaling is transmitted over the same channel as the voice path (unlike
PRI, ISDN, SS7, or SIP where the call control is
transmitted via data channels or separate paths).
CLEC (Competitive Local Exchange Company)
Telephony company (not a Bell Operating Company) that competes for business in the local telephone market.
DID (Direct Inward Dial)
Inbound-only phone number assigned to a group of phone lines that
allows a phone system to route to a unique location or person. A group
of DIDs is often assigned to a single trunk group. DID numbers are not
sent out as the ANI when the caller places an outbound call.
DNIS (Direct Number Identification Service)
Feature that sends all or part of the dialed number to a telephony system
DNC (Do Not Call)
National registry created to let consumers
block incoming telemarketing calls. If you choose to add your phone
number to this list, it shows up on the registry by the next day.
Telemarketers have up to 31 days to remove your number from their call lists.
Series of telephone lines organized so that when the first
line is busy, the next line is hunted and so on until a free line is found.
IP (Internet Protocol)
The main communications protocol on which the internet is based. It allows packets of data to be routed and traverse multiple networks on the way to its final destination.
IVR (Interactive Voice Response)
Telephony system that automatically answers incoming calls, provides
greetings, menus, and prompts, then routes calls
based upon the callers ANI or DTMF (dual-tone-multi-frequency, also known as touch-tone) digits received by
ISDN (Integrated Services Digital Network)
In the telephony world, ISDN is often interchanged with the term PRI
(Primary Rate Interface) which is a T1 (group of 24 digital trunks)
where the channels 1-23 are utilized for voice, and the 24th channel
is utilized for call control.
Small digital phone system (usually 2-6 analog lines) that provides
limited PBX functionality to a small number of users.
LEC (Local Exchange Carrier)
Local phone company, which can be either a Bell Operating Company or an independent,
which traditionally had the exclusive right to provide local telephone service.
Same as a telephone number. Any 10 digit LEC-assigned (non toll free) phone number that can be dialed
from anywhere in the world. Includes all types of local numbers, such as ANIs, DIDs,
and RCFs. If a caller must dial a 1 to reach this number, the caller is
responsible for the per-minute costs.
LNP (Local Number Portability)
Ability of telephone subscribers to maintain their phone numbers
when they change local telephone companies or toll free number providers.
MOS (Mean Opinion Score)
International standard that is used to measure the voice quality of a
phone call. It uses a scale of 1 to 5, where 5 is the best quality . A score of 4.0 or better is considered PSTN
NOC (Network Operations Center)
Secure and environmentally-controlled data center that houses critical
telephony equipment and servers that are essential for operations.
NPA (Numbering Plan Area)
Area code (first 3 digits) of any 10 digit telephone number.
Digits 4, 5 and 6 of a 10 digit telephone number (often referred to as the
prefix) where N is any digit 2-to-9. X is any digit 0-to-9. These
digits typically identify the telephone company central office that serves that telephone number
PBX (Private Branch Exchange)
Large phone system that is capable of supporting hundreds or thousands
of extensions. Can integrate a multitude of features (such as ACD,
queue, voice mail, conferencing calling, etc.) and typically utilizes
PRIs or VoIP to connect to the local service provider where incoming
calls are routed utilizing DIDs.
POP (Point of Presence)
Any location where hardware that services a telephony network is located. Is a smaller version of a NOC.
POTS (Plain Old Telephone Service)
Basic dial tone service provided via copper wires directly from the local service provider.
PRI (Primary Rate Interface)
A T1 (group of 24 digital trunks) where channels 1-23 are for voice, and channel 24 is for call control. Commonly
found in larger phone systems or PBXs. There are many flavors of PRI.
PSTN (Public Switched Telephone Network)
Worldwide voice telephone network accessible to all those with telephones and access privileges.
QOS (Quality of Service)
In the telephony world, specifies the guaranteed throughput or quality of bandwidth used to route VoIP calls.
Telephony system that stacks or holds calls to be handled by a
specific person or group. Often used in call centers, or with
phone systems that handle large quantities of incoming calls.
RCF (Remote Call Forward)
Phone number assigned by the local phone company that has no physical
location. When called, it forwards to another pre-determined phone
number. The forward-to number can be changed only by the local phone
Destination number associated with a toll free number. Is typically the customers main phone number.
RespOrg (Responsible Organization)
Telecommunications providers responsible for obtaining and
managing toll free numbers from the Service Management System (national
toll free routing database).
Call that rang through to the destination, but was un-answered.
SIP (Session Initiation Protocol)
Internationally recognized IP telephony signaling protocol used for VoIP.
Device that converts one type of telephony protocol to another. Often used with traditional telephony systems
to allow them to utilize VoIP.
Service Management System database responsible for routing every toll free call made
within North America. Contains information about which
carrier will route the call, which RespOrg is responsible, and who the
customer of record (the owner) is for each toll free number. Only RespOrgs are
given direct access into this database.
High-density software-enabled approach to telephony switching that
allows for rapid feature deployment and increased functionality within a
switching platform. Has the potential to address all the
shortcomings of traditional switches (scalability, smaller footprint,
quicker feature creation, cost of operation, database integration, API, et al.).
SS7 (Signaling System 7)
International signaling standard for all digital exchanges with
integrated services. Allows call control to be
transferred on communications paths that are separate from the voice and data connections
Large-scale telephony platform used to route phone calls through the PSTN.
Dedicated phone or bandwidth connection that supports data rates of 1.54 Mbits per second. A voice T1 consists of 24 individual channels, each of which can be configured to support voice or data with up to 64k
per second. The most common T1s are PRIs into PBXs configured as either local dial tone circuits or dedicated long distance circuits.
TCAP (Transaction Capability Application Part)
Portion of the SS7 protocol used to query databases and
route calls according to the results. Used by every local service provider in North America to determine which carrier to
route toll free calls to.
TFN (Toll Free Number)
800, 866, 877, or 888 numbers that can be dialed from anywhere in North
America, and are reverse-billed. The owner or company the TFN
routes to is responsible for the per-minute costs, and the call is free
of charge to the calling party. When dialing a TFN, the caller gives up
their legal right of autonomy, and their phone number can be displayed
to the called party, even if Caller ID block is enabled on the callers line.
TN (Telephone Number)
Same as Local Number. Any 10 digit LEC-assigned (non toll free)
phone number that can be dialed from anywhere in the World. Includes all types of local numbers, such as
ANIs, DIDs, and RCFs. If
a caller must dial a 1 to reach the number, the caller is
responsible for the per-minute costs.
Phone line or voice path that can be used or shared across multiple voice applications.
VoIP (Voice over IP)
Process of transmitting voice traffic across a packet (data) network, typically utilizing SIP.
VPN (Virtual Private Network)
Private data network that makes use of the PSTN or internet,
maintaining privacy through the use of a tunneling protocol and security
procedures. This is often used in conjunction with VoIP as a more
cost-affective alternative to a dedicated bandwidth connection.