Toll-free telephone numbers in the North American Numbering Plan

In the United States of America, Canada, and other North American Numbering Plan countries, a toll-free telephone number has one of the area codes 800, 844, 855, 866, 877, and 888.

Area codes 833 and 822 are expected to be used in the future, followed by 880 through 887, then 889. However, 811 is reserved as a three-digit number for various other purposes. In addition, 899 is reserved as a member of the series x9x for future numbering plan expansion.

Calls to these numbers are free to the caller if dialed from land-line phones but may incur mobile airtime charges for cellular phones.

History

Unlike the United Kingdom, most of the United States and all of Canada uses a rate structure in which local calls are flat-rated and incur no per-call cost to residential subscribers. As regulators in North America had long allowed long-distance calling to be priced artificially high over the many decades of Bell System monopoly in return for artificially low rates for local service, subscribers tended to make toll calls rarely and keep them deliberately brief.

A few businesses, eager to sell their products to buyers outside the local calling area, were willing to accept collect calls where they paid the cost of receiving telephone enquiries. Initially, all of these calls had to go through the telephone company's operator, who requested acceptance of the charges for each call manually. An early refinement of this process, in the late 1950s, was for businesses to publish a Zenith number (because, at that time, the letter "Z" was not present on the telephone dial) in various out-of-town directories for towns from which they would accept all charges-reversed calls. This saved a small amount of time, but an operator still had to manually find the underlying number on a printed list and place the call with charges billed to the called party.

The first automated toll-free 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. There was no itemised billing of calls and the expensive fixed-rate line was only within financial reach of large corporations and government agencies.

In the early 1980s, Bell Labs patented what became AT&T's "Advanced 800 Service" – a computer-controlled system where any toll-free number could point anywhere (such as to a small business local number instead of a special InWATS line) and an itemised bill generated for only 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.

Operation

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 (voice-over-IP, pocket pagers, residential and small business use) and widespread abuse by RespOrgs and subscribers who stockpile the numbers for use in misdial marketing (PrimeTel Communications alone ties up millions of numbers), response tracking for individual advertisements (each ad from each client gets a different freephone number) or sale, lease or shared use (brokering numbers for sale is illegal, but renting a number or part of a number circumvents these regulations as FCC enforcement is sporadic to minimal).

Some geographic area codes are similar to the toll-free codes, e.g., 801, 818, 860. Such similarities have been exploited by fraudsters in international locations that can be direct-dialed with what appear at first glance to be domestic area codes, including 809, 829, and 849, which are official prefixes for the Dominican Republic and 876 which is the area code for Jamaica. 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 phone 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 payphones. Calls from payphones 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 MCI Worldphone international calling card and any US-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 UK), US 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.

US toll-free numbers could at one time be accessed from certain other countries (such as Mexico) on a paid basis by replacing the 800 by 880, 888 by 881, and 877 by 882. Thus, to reach 1-800-xxx-yyyy from a country outside its toll-free coverage area, 1-880-xxx-yyyy could be dialed. This is no longer true; area codes 880, 881 and 882 have since been reclaimed for future use.

In addition, US toll-free numbers may be accessed free of charge regardless of the caller's location by some IP telephone services.

How toll-free calls are handled by operators

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. The way that a toll-free number is handled depends on whether it is a domestic or interexchange call. Most countries are divided into regions called exchanges, and within each exchange a local telephone company handles all phone services.[1] 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 interexchange calls.

The format of the toll-free number is called a non-geographic number, in contrast to telephone numbers associated with households which are geographic. (Since the advent of cell phones and voice over IP, households can have any area code in the U.S. —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. This is achieved using the intelligent network capabilities embedded into the network.

In the simplest case, the toll-free number is translated into a regular geographic number. This number 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.

Technical description of toll-free number 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. 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.

When a toll-free number is dialed, each digit is analysed 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 signalling 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 that 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:

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. [Edited]

Assignment of NANP toll-free telephone numbers

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:

References

  1. ↑ "What Is a Toll-Free Number and How Does it Work?". Federal Communications Commission. Retrieved September 12, 2013.
  2. ↑ "800-855 Line Numbers". North American Numbering Plan Administration. Retrieved August 22, 2014.
    This article is issued from Wikipedia - version of the 12/4/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.