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.
Phonewords are the most common , although a few all-numeric vanity phone numbers are used. Toll-free telephone numbers are often branded using phonewords; some firms use easily memorable vanity telephone numbers like 1-800 Contacts, 1-800-Flowers, 1-866-RING-RING, or 1-800-GOT-JUNK? as brands for flagship products or names for entire companies.
Local numbers are also occasionally used, such as +1-514-AUTOBUS or STM-INFO to reach the Société de transport de Montréal, but are constrained by the fact that the first few digits are tied to a geographic location, potentially limiting the available choices based on which telephone exchanges serve a local area.
However, devices which have virtual keyboards, including iOS and Android devices, will translate phoneword phone numbers in webpages and SMS messages to their proper digits within a hyperlink leading to that device's phone app, and their keypads show the appropriate local mapping of letters within their virtual dialpad.
Some models of smartphones allow the user to enter letters into the device’s dialing window to allow the completion of phonewords. Numerous Blackberry models allow this feature by using the ALT key when pressing a key to select the letter, and not the number on the key.
On older landline telephones, the O, Q and Z sometimes vary in placement or are omitted entirely; this is not an issue for most mobile telephones as all 26 letters must be provided to support short message service transmission.
The dialing of 1 or 0 instead of I or O in phonewords can lead to ; one such typosquatting incident targeted 1-800-HOLIDAY (+1-800-465-4329, the toll-free direct reservations line for Holiday Inn) by subscribing 1-800-H0LIDAY (+1-800-405-4329, the same number with 'o' replaced by 'zero') to a rival vendor which stood to collect a profitable travel agent's commission. 86 F.3d 619, 65 USLW 2026, 39 U.S.P.Q.2d 1181: HOLIDAY INNS, INC. vs 800 RESERVATION, INC, Earthwinds Travel, Inc. and Call Management Systems, Inc, United States Court of Appeals, Sixth Circuit. June 24, 1996.
Some phonewords have sold for as much as A$1 million with 13TAXI raising A$1,005,000. Proposed ranges for reserve prices for SmartNumbersTM are listed by Australian Communications Authority
The types of numbers that are most commonly used include those beginning with the prefixes '1300', and '1800', which are ten digits long, and numbers beginning with '13', which are six digits.
The differences between the prefixes are the length of the number (six or ten digits), the license cost to use them each year (approximately A$1 for 1800 and 1300, A$10,000 for 13 numbers) and the call cost model. 1300 numbers and 13 numbers share call costs between the caller and call recipient, whereas the 1800 model offers a national free call to the caller, with total costs of the call borne by the recipient.
Local telephone numbers have always been subject to the constraint that the first digits must identify a geographic location, leaving less flexibility to select digits which spell specific phonewords. Toll-free numbering, as originally introduced by AT&T in 1967, was initially even more limited, as each geographic area code was hardwired to one or two specific exchanges in the +1-800 toll-free area code. This changed after Roy P. Weber of Bell Labs patented a "Data base communication call processing method" which laid the initial blueprint for construction of the SMS/800 database in 1982 and the portable RespOrg structure in 1993. A toll-free number, instead of indicating a geographic location, was merely a pointer to a database record; any number could geographically be reassigned anywhere and ported to any carrier. All seven digits were available to construct vanity numbers or phonewords.
As toll-free telephone numbers, vanity 800 numbers support flexible DNIS which allows businesses to determine where their incoming call traffic is coming from, build a database of leads, access demographic information on callers, allocate personnel based on calling patterns, analyze ad campaign results and export data to other programs. The reports help to fine-tune advertising plans and media budgets by providing detailed information on specific media buys (such as radio, television or outdoor media).
Some companies also match domain names to phone words (for instance, 1800-THRIFTY and the web site ) to target phone and web users together.
One brief practice was when the successive toll-free area codes were introduced (888, 877, 866, etc.), a business word or phrase would actually use one or more of the numbers in the area code. Examples of this were Rent-A-Wreck (1-87-RENT-A-WRECK or 1-US-RENT-A-WRECK), Speedpass (1-87-SPEEDPASS), and one of the first Vonage numbers (1-VONAGE-HELP). However, these proved to be more confusing than helpful to the callers, so the practice is not often used.