Toll-free telephone numbers in the North American Numbering Plan

Last updated

Toll-free telephone numbers in the North American Numbering Plan have the area code prefix 800, 833, 844, 855, 866, 877, and 888. Additionally, area codes 822, 880 through 887, and 889 are reserved for toll-free use in the future. 811 is excluded because it is a special dialing code in the group NXX for various other purposes.


Calls to the toll-free numbers are charged to the receiving party, and are free to the caller if dialed from land-line telephones, but may incur mobile airtime charges for cellular service.


Most carriers in the United States and in all of Canada use flat-rate billing for local calls, which incur no per-call cost to residential subscribers. Long-distance calls have higher prices. As regulators in North America had long allowed long-distance calling to be priced artificially high in return for artificially low rates for local service, subscribers tended to make toll calls rarely and to keep them deliberately brief.[ citation needed ]

Some businesses, targeting to sell products to buyers outside the local calling area, were willing to accept collect calls or installed special services, such as Zenith number service, where they paid the cost of receiving telephone enquiries. Initially, all of these calls had to be completed by the switchboard operator.

The first automated toll-free telephone numbers were assigned with area code 800, created as inbound Wide Area Telephone Service (InWATS) in 1966 (U.S. intrastate) and 1967 (interstate). These terminated on special fixed-rate trunks which would accept calls from a specified calling area with either no limit or a specific maximum number of hours per month. The billing of calls was not itemized and the expensive fixed-rate line was only within financial reach of large corporations and government agencies. Typically, a service provider offered a variety of zones, each costing more than the smaller ones, but adding progressively larger areas from which calls would be accepted for a customer.

In the early 1980s, Bell Labs received a patent for what became AT&T's "Advanced 800 Service", a computer-controlled system where any toll-free number could point to any destination number, such as to a small business local number instead of a special InWATS line, and an itemized bill generated only for the calls the business actually received. By breaking the link between the number's exchange prefix and geographic location, this system opened opportunities for vanity number advertising – an advantage in media like commercial radio where numbers need to be memorable.

The toll-free long distance market was opened to competition after 1986 and a RespOrg system instituted in 1993 to provide toll-free number portability between rival carriers using the SMS/800 database. Open competition also brought an end to the pattern of long distance subsidizing local service, bringing per-minute charges down to levels where any business could afford to take orders using an 800-number.

Originally, 800 service in the US and 800 service in Canada were isolated from each other, but in 1984, an agreement between carriers in the two countries allowed the numbers in each country to be accessible to the other; providers of 800 service were able to add zones to cover the expanded areas able to be offered. The arrival of Advanced 800 Service meant that numbers originally limited to use in Canada became available to American customers, and vice versa.


Toll-free telephone numbers in the NANP are regulated by the Code of Federal Regulations (CFR) Part 52 Section 101. RespOrgs assign the numbers in the SMS/800 database. SMS/800, Inc. administers this database as the Number Administration and Service Center, as a subcontractor for the Federal Communications Commission (FCC).

The SMS/800 database and RespOrg structure are used in the U.S. and Canada. A few specific exchanges remain reserved or are assigned to specific North American Numbering Plan countries which do not draw numbers from the SMS/800 pool:


The original 800-code operated for over thirty years before its 7.8 million possible numbers were depleted, but new toll-free area codes are being depleted at an increasing rate both by more widespread use of the numbers by voice-over-IP, pocket pagers, residential, and small business use, and response tracking for individual advertisements (each ad from each client gets a different freephone number) or sale, lease or shared use.

Some geographic area codes are similar to the toll-free codes, e.g., 801, 818, 860. Toll-free numbers are also sometimes confused with 900-numbers, for which the telephone company bills the callers at rates far in excess of long-distance service rates for services such as recorded information or live chat.

These toll-free numbers can normally be called from any telephone in Canada or the U.S., though the owner (and sometimes the provider) can put restrictions on their use. Sometimes they accept calls only from either Canada or the U.S., or even only from certain states or provinces. Some are not accessible from pay phones. Calls from pay phones assess the toll-free owner an additional fee in the U.S., as mandated by the FCC. Although toll-free numbers are not accessible internationally, many phone services actually call through the U.S., and in this case the toll-free numbers become available. Examples of these services are the erstwhile MCI Worldphone international calling card and any U.S.-based Internet telephone gateway. However, many calling card services charge their own fee when their toll-free numbers are used to make calls or when their toll-free numbers are used from pay phones.

From many countries, such as the U.K., U.S. toll-free numbers can be dialed, but the caller first gets a recorded announcement that the call is not free; in fact, on many carriers, the cost of calling a "toll-free" number can be higher than that of calling a normal number.

Operator handling

In the United States, both interexchange carriers (IXCs) such as Sprint, AT&T Inc., and Verizon, and Local Exchange Carriers (LECs) such as Verizon and AT&T offer toll-free services. [2] [3] The way that a toll-free number is handled depends on whether it is a domestic or an interexchange call. Most countries are divided into regions called exchanges, and within each exchange a local telephone company handles all phone services. [4] Intraexchange calls, which do not leave the individual region, would be managed by the individual local telephone company. Calls that cross U.S. LATA boundaries, or originate in one country and terminate in another, are referred to as inter-exchange calls.

The format of the toll-free number is called a non-geographic number, in contrast to telephone numbers associated with households that are geographic. (Since the advent of cell phones and voice over IP, households can have any area code in the U.S., but it is still geographic in the sense that calls from that area code are considered local, but the recipient can be physically anywhere). In the latter case, it is possible to determine an approximate location of the caller from the area code (e.g. New York or London). In contrast, toll-free numbers could be physically located anywhere in the world.

When a toll-free number is dialed, the phone company must determine where the actual physical destination is, which is achieved by using the intelligent network capabilities embedded into the network. In the simplest case, the toll-free number is translated into a regular geographic number, which is then routed by the telephone exchange in the normal way. More complicated cases may apply special routing rules in addition such as Time of Day routing.

Toll-free numbers are normally specific to each country. Canadian numbers are an exception as they are drawn from the same SMS / 800 pool as other North American Numbering Plan countries; the +800 Universal International Freephone Number is an exception as these work from multiple country codes. The arbitrary distinctions between Local Exchange Carrier / Interexchange carrier, intrastate / interstate and the LATA structure are artificial U.S. regulatory constructs which do not have direct parallels in Canada or any other nation.

Routing in the U.S.

The IXCs generally handle traffic crossing local access and transport area (LATA) boundaries. A LATA is a geographical area within the U.S. that delineates boundaries of the LEC. [5] LECs can provide local transport within LATAs. When a customer decides to use toll-free service, they assign a Responsible Organization (RespOrg) to own and maintain that number. The RespOrg can be either the IXC that is going to deliver the majority of the toll-free services or an independent RespOrg. [6]

When a toll-free number is dialed, each digit is analyzed and processed by the LEC. The toll-free call is identified as such by the service switching point (SSP). The SSP is responsible for sending call information to the service control point (SCP), routing the request through at least one signal transfer point (STP) in the Signalling System 7 (SS7) network. SS7 is a digital out-of-band method of transmitting signalling (call control) information in the Public Switched Telephone Network (PSTN). The SS7 network is a packet-switched network carrying signaling data (setup and tear down of the call and services) separate from the circuit-switched bearer network (the payload of the telephone call) in the AIN services network. The SSP asks the SCP where to send the call.

The LEC will determine to which IXC that number is assigned, based on the customer's choice. Toll-free numbers can be shared among IXCs. A customer may do this for disaster recovery or so they can negotiate a better price. For example, a customer may assign 50% of their traffic to Sprint and 50% to AT&T.

Once the LEC determines to which IXC to send the call, it is sent to the IXCs point of presence (POP). The IXCs SCP must now determine where to send the call. Once the final determination of where the call is supposed to go is completed, the call is then routed to the subscriber's trunk lines. In a call center or contact center environment, the call is then typically answered by a telephone system known as an automatic call distributor (ACD) or private branch exchange (PBX).

The subsequent routing of the call may be done in many ways, ranging from simple to complex depending on the needs of the owner of the toll-free number. Some of the available options are:

Time-of-Day (TOD) routing
An example of using TOD routing would be a company with a call center on the east coast and a call center on the west coast. TOD routing would enable Follow the Sun routing. The east coast center opens first and calls are sent to that destination earlier in the day. As the time changes across the country, expanded coverage would be offered by the call center in the west. [7]
Day of Week (DOW) or Day of Year (DOY) routing
Depending on the day of the week and business practices, not all call centers operate 24×7. Some centers may be closed for weekends or holidays. DOW routing allows alternate routing for calls that arrive on specific days. DOY routing allows for alternate routing on fixed holidays (example December 25).
Area Code or Exchange routing
Toll-free traffic may also be routed depending upon the location of the caller. For instance, if a company has call centers in the north and in the south, they may express a preference to have their southern callers speak with people in the southern call centers. Companies may also wish to take advantage of the difference in interstate rates versus intrastate rates. For example, the cost of a telephone call across multiple states may be less expensive than a call within a state, and as a result, the ability to route a call originating in Michigan to a call center outside Michigan can save a company substantial amounts of money.
Least-Cost routing
Least-Cost routing is a variant of area code / exchange routing in which an independent RespOrg sends calls via different carriers based on which is least expensive for any given origination point. The RespOrg is not the carrier. A Canadian carrier could be used for Canadian calls and a U.S. carrier for American calls; a user with many inbound local voice over IP numbers in multiple cities could convert toll-free calls on one main toll-free number to local calls in each city where it has a point of presence.
Percentage Allocation routing
If a company has multiple call centers, the company can choose to route calls across a number of call centers on a percentage basis. For example, an airline with ten call centers may choose to allocate 10% of all incoming traffic to each center.
All-Trunks-Busy routing
If at a given time a company's trunk facilities can no longer handle the incoming traffic, an alternate destination may be chosen. This assists companies handling unexpected call volumes or during crisis times.
Ring No Answer Routing
Some carriers have the ability to pull a call back into the network if the call is not answered. This provides for contingency routing for calls that ring and are not answered at the final destination.
Emergency or Disaster routing
Companies usually have some type of disaster plan to deal with both natural (e.g. floods, fires and earthquakes) and man-made (e.g. bomb threats) emergencies. IXCs can provide alternate destinations should any of these situations occur.
Take Back and Transfer / Transfer Connect / Agent Redirect
If a company uses an ACD to facilitate the transfer, the ACD will remain in the call as long as the parties are on the phone. The drawback is that this uses up trunk capacity on the ACD (or VRU). This is called by a number of names including hair-pinning or tromboning. IXCs have the capability to allow a company to answer a call, provide a level of service, and then transfer the call to another location. These IXC features provide a level of transferring that is different from what is available via the ACD. There is usually a feature charge associated with this offering.

All of the above routing features are sometimes referred to as static routing features. These routes are put in place and are not usually changed. If changes are required, a customer usually has several options to make changes. A customer can call the IXC or an independent RespOrg directly via a special toll-free number to make changes, or a customer may be able to make changes through direct access to the network via a dedicated terminal provided by the IXC.

Related Research Articles

An automatic number announcement circuit (ANAC) is a component of a central office of a telephone company that provides a service to installation and service technicians to determine the telephone number of a telephone line. The facility has a telephone number that may be called to listen to an automatic announcement that includes the caller's telephone number. The ANAC facility is useful primarily during the installation of landline telephones to quickly identify one of multiple wire pairs in a bundle or at a termination point.

Wide Area Telephone Service (WATS) was a flat-rate long-distance service for customer dial-type telecommunications in the service areas of the North American Numbering Plan (NANP).

Local exchange carrier (LEC) is a regulatory term in telecommunications for the local telephone company.

An interexchange carrier (IXC), in U.S. legal and regulatory terminology, is a type of telecommunication company, commonly called a long-distance telephone company. It is defined as any carrier that provides services across multiple local access and transport areas (interLATA). Calls made on telephone circuits within the local geographic area covered by one local network are handled only by that intraLATA carrier, commonly called a local telephone exchange carrier. Local calls are usually defined by connections made without additional charge whether the connected call is in the same LATA or connects to another LATA with no charge. IntraLATA usually refers to rated or toll calls between LATA within state boundaries, as opposed to interstate, or calls between LATAs in different states.

<span class="mw-page-title-main">North American Numbering Plan</span> Integrated telephone numbering plan of twenty North American countries

The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the telephone country code 1. Some North American countries, most notably Mexico, do not participate with the NANP.

Automatic number identification (ANI) is a feature of a telecommunications network for automatically determining the origination telephone number on toll calls for billing purposes. Automatic number identification was originally created by the American Telephone and Telegraph Company (AT&T) for long distance service in the Bell System, eliminating the need for telephone operators to manually record calls.

4-1-1 is a telephone number for local directory assistance in Canada and the United States. Until the early 1980s, 4-1-1 — and the related 1-1-3 number — were free to call in most states.

A toll-free telephone number or freephone number is a telephone number that is billed for all arriving calls. For the calling party, a call to a toll-free number from a landline is free of charge. A toll-free number is identified by a dialing prefix similar to an area code. The specific service access varies by country.

In telecommunications, directory assistance or directory inquiries is a phone service used to find out a specific telephone number and/or address of a residence, business, or government entity.

<span class="mw-page-title-main">Telephone numbers in Australia</span>

The Australian telephone numbering plan governs the allocation of telephone numbers in Australia. It has changed many times, the most recent major reorganisation by the Australian Communications and Media Authority taking place between 1994 and 1998.

In telecommunications, a long-distance call (U.S.) or trunk call is a telephone call made to a location outside a defined local calling area. Long-distance calls are typically charged a higher billing rate than local calls. The term is not necessarily synonymous with placing calls to another telephone area code.

Telephone number pooling, thousands-block number pooling, or just number pooling, is a method of allocating telephony numbering space of the North American Numbering Plan in the United States. The method allocates telephone numbers in blocks of 1,000 consecutive numbers of a given central office code to telephony service providers. In the United States it replaced the practice of allocating all 10,000 numbers of a central office prefix at a time. Under number pooling, the entire prefix is assigned to a rate center, to be shared among all providers delivering services in that rate center. Number pooling reduced the quantity of unused telephone numbers in markets which have been fragmented between multiple service providers, avoided central office prefix exhaustion in high growth areas, and extended the lifetime of the North American telephone numbering plan without structure changes of telephone numbers. Telephone number pooling was first tested for area code 847 in Illinois in June 1998, and became national policy in a series of Federal Communications Commission (FCC) orders from 2000 to 2003.

Direct inward dialing (DID), also called direct dial-in (DDI) in Europe and Oceania, is a telecommunication service offered by telephone companies to subscribers who operate a private branch exchange (PBX) system. The feature provides service for multiple telephone numbers over one or more analog or digital physical circuits to the PBX, and transmits the dialed telephone number to the PBX so that a PBX extension is directly accessible for an outside caller, possibly by-passing an auto-attendant.

<span class="mw-page-title-main">Telephone numbers in Romania</span>

The dialling plan for mobile networks and new landline operators is closed; all subscriber numbers must be dialled in full. For landline numbers starting with 02, the dialling plan used to be open; the trunk digit and area code could be omitted if the caller was in the same area code as the callee. However, starting May 3, 2008, all landline numbers must be dialled in full.

<span class="mw-page-title-main">Phoneword</span> Mnemonic phrases represented as alphanumeric equivalents of a telephone number

Phonewords are mnemonic phrases represented as alphanumeric equivalents of a telephone number. In many countries, the digits on the telephone keypad also have letters assigned. By replacing the digits of a telephone number with the corresponding letters, it is sometimes possible to form a whole or partial word, an acronym, abbreviation, or some other alphanumeric combination.

A RespOrg, or responsible organization, is a company that maintains the registration for individual toll-free telephone numbers In the North American Numbering Plan by means of the distributed Service Management System/800 database.

The line information database (LIDB) is a collection of commercial databases used in the United States and Canada by telephone companies to store and retrieve Calling Name Presentation (CNAM) data used for caller ID services. In Canada, it is common for the client to apply their own Caller ID information, and this is allowed, provided the regulations regarding spoofing and fraud are not violated. The databases map telephone numbers to 15-character strings of caller names. Class 5 telephone switches, which provide end-office services in exchange areas, use the Signaling System 7 (SS7) signaling protocol to query the database.

<span class="mw-page-title-main">PSTN network topology</span>

PSTN network topology is the switching network topology of a telephone network connected to the public switched telephone network (PSTN).

Toll-free number portability or freephone number portability allows the subscriber of a freephone number to switch providers while retaining the same number for incoming calls. Similar schemes exist in many countries for local number portability and mobile number portability, although implementation details for each portability scheme varies between countries.

Somos, Inc., is a company that manages registry databases for the telecommunications industry. Additionally, since January 1, 2019, the company has been the North American Numbering Plan Administrator, under a contract granted by the Federal Communications Commission.


  1. "800-855 Line Numbers". North American Numbering Plan Administration. Retrieved August 22, 2014.
  2. "IP Telephony & Toll-Free Number Service at AT&T Business". AT&T Business. Retrieved 2020-11-13.
  3. "Toll Free & Inbound Services". Verizon Business. Retrieved 2020-11-13.
  4. "What is a toll-free number and how does it work?". Federal Communications Commission. Retrieved September 12, 2013.
  5. "What is a LATA?". Bandwidth. Retrieved 2020-11-13.
  6. Wolf, Jon. "Home". Retrieved 2020-11-13.
  7. "Configure Time of the Day Routing". Cisco. Retrieved 2020-11-13.