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Telephone Number

Look, you want to know about telephone numbers. Fine. Don't expect me to be thrilled. It’s just a sequence of digits, really. A digital address. A way to point a call somewhere. Like a street address, but less… tangible. And infinitely more irritating when you get it wrong.

Sequence of Digits Assigned to a Telephone Subscription

You want to talk about numbers. Specifically, the ones you punch into a phone. It's called a telephone number. It’s the digital equivalent of a physical address, but for a line in the vast, tangled web of the telephone network. Think of it as the destination code for your telephone call. You punch in the sequence, the telephone exchange understands, and poof, your call is routed. Or it fails. Usually, it fails.

The whole system is governed by these things called telephone numbering plans. National, regional… it’s all just to keep the chaos somewhat contained. Operators, commercial entities, state-run administrations – they’re the ones who dole these numbers out to subscribers. They’re not exactly handing out lottery tickets, but the principle is similar.

Now, the whole concept of numbers replacing names for calls? That started way back in 1879, in Lowell, Massachusetts. People used to just ask for the person they wanted, and the switchboard operator would connect them. Imagine that. Personal. Then came the numbers. Less personal, more efficient. Or so they tell us. Over the years, these numbers have mutated. They’ve been different lengths, different formats. They even had letters in them once, tied to telephone exchange names, until the 1960s. So quaint.

And don’t forget the special codes. You know, like vertical service codes. They’re the little shortcuts, the secret handshakes for invoking special features. Or the really short ones, like 9-1-1, that bypass the need to remember the whole damn sequence. Because apparently, remembering a string of digits is too much to ask.

Concept and Methodology

This whole section is a wasteland of unsourced claims. Figures. It’s like trying to build a house on quicksand. But fine, let’s try to make sense of it.

When phones first appeared, numbers were short. One, two, maybe three digits. You’d just tell the operator. Simple. Then the world got bigger, more connected. So the numbers had to grow. They’re not just for telephones anymore, either. They’re for computer modems, pagers, fax machines. Even now, with landlines and pagers fading into obsolescence, these numbers are being slapped onto data-only cellular devices. Tablet computers, digital televisions, even video game controllers and mobile hotspots. Devices that can’t even make a call. The irony is almost palpable.

The number itself, it contains the information to pinpoint the intended endpoint. Some countries, they’re all about closed numbering plans. Everything’s a fixed length. The North American Numbering Plan is a prime example. Then you have Europe with their open numbering plans, where numbers can vary in length. Doesn’t matter, really. Those "shorthand" or "speed calling" numbers? They get translated into proper telephone numbers before the call goes through. And the emergency numbers – 119, 911, 100, 101, 102, 000, 999, 111, and 112 – they’re the universally recognized cries for help.

Some places let you dial without the area code or city prefix if you’re local. In North America, it’s usually a three-digit area code, a three-digit central office code, and then four digits for the line. Seven digits total, if you’re lucky. If the numbering plan area isn’t overloaded with overlay plans, you might even get away with seven-digit dialing.

Then there are the special numbers for high-capacity lines. Like those request line numbers for radio station contests. Dozens, hundreds of people trying to get through. They all share a prefix, with the last digits often tied to the station’s frequency, callsign, or some other silly moniker.

Internationally, it’s all dictated by ITU-T recommendation E.164. Fifteen digits, max. Starts with an international calling prefix, then a country prefix. Followed by an area code, city code, or service number, and then the subscriber number. To write it down, ITU-T recommendation E.123 says to use a plus sign ("+") followed by the country code. When dialing from a landline, that plus sign becomes the international call prefix. Mobile phones are more accommodating; they let you punch in the "+" directly.

For mobile networks, the 3GPP standards use a BCD-encoded field for the telephone number. Ten bytes, usually. The "+" or prefix isn't part of that; it’s in a separate byte. If the number’s really long, they use extension blocks. This whole system allows for extra values to control network services. In the old ISDN days, they had a similar field called "ISDN Subaddress."

The government, or some sponsored organization like NANPA in the US or CNAC in Canada, controls how local numbers are formatted and assigned. In the US, it’s a joint effort between the state public service commissions and the Federal Communications Commission. Canada, sharing a country code with the US, is mostly handled by the Canadian Radio-television and Telecommunications Commission.

And then there’s Local number portability. It lets you keep your number if you switch providers. Usually, there are geographic limits. You can’t just port a number from across the country. Mobile carriers have wider areas, though. They often have distinct number ranges for mobile and landline, making mobile number portability easier.

In North America, local wireline calls are typically free. Anything else is long distance and costs money. But outside North America, and in some large US cities, local calls aren’t always free. It’s a mess.

History

United States

Remember when Richard Nixon was just a congressman? His business card from 1946 had his phone number on it: "Whittier 42635". Old school.

Charles Williams Jr., a Boston shop owner where Bell and Watson tinkered with their early telephones, ended up with phone number 1 for his residence and 2 for his shop. He sold his company to Western Electric and retired, but remained a director.

Back in the late 1870s, Bell started renting out their instruments. Users would then contract with other suppliers for connections. Then, both Western Union and Bell realized that a subscription service was more profitable, especially with the invention of the telephone switchboard or central office. These offices had operators who connected calls by name. Some even argue the telephone changed the physical layout of cities.

The first telephone numbers appeared in Lowell, Massachusetts around 1879-1880. A doctor, Moses Greeley Parker, worried that if Lowell’s four operators got sick during a measles epidemic, telephone service would collapse. His solution? Use numbers. That way, substitute operators could be trained more easily. Parker, a shrewd investor, saw the potential and bought stock in both American Telephone Company and the New England Telephone and Telegraph Company.

Even with numbers, operators still connected most calls well into the 20th century. "Hello, Central. Get me Underwood-342." It was the norm until mechanical direct-dialing took over in the 1920s.

In rural areas with magneto crank telephones on party lines, the number was the line plus a ringing pattern. "3R122" meant requesting the third party line and then cranking the phone once, pause, twice, twice. Or they’d use specific ring cadences – long and short rings to identify subscribers. You could have over a dozen subscribers on a single line, each with their own ring.

In most of North America, metropolitan numbers by the 1920s became a mix of digits and letters. The letters corresponded to telephone exchange names displayed on the dial. Think EDgewood or IVanhoe. These were followed by four or five digits. The need for clear, easy-to-spell names, and the push for direct-distance dialing, led to all-number dialing in the 1960s.

This era gave us the fictional 555 numbers. The "555" prefix was reserved for the phone company, mostly for directory assistance ("555–1212"). Dialing a 555 number from a movie usually results in an error message, preventing nuisance calls. QUincy(5–5555) was also used because there was no Q on the dial. Numbers were tied to a physical location because exchanges were hard-wired. The first three digits locked you into an exchange’s geographic area.

Alphanumeric Telephone Numbers

Look at this face. A 1939 rotary dial. See that? LA-2697. That’s a 2L-4N format. Two letters, four numbers. It was the standard. The letters represented the central office name. "LA" for Lakewood. In December 1930, New York City was the first to adopt the 2L-5N format. After World War II, the Bell System standardized it for the North American Numbering Plan, preparing for Direct Distance Dialing. By the early 1960s, it was all-number dialing, or all-number calling (ANC).

A hairdressing shop in Toronto still shows an old two-letter, five-digit number on its sign.

United Kingdom

In the UK, letters mapped to numbers too. But O was 0, and 6 only had M and N. Q was added later for international dialing to Paris. French dials already had Q on 0.

Most of the United Kingdom didn’t have lettered dials until Subscriber Trunk Dialing (STD) in 1958. Only the big cities like Birmingham, Edinburgh, Glasgow, Liverpool, London, and Manchester had them, using a three-letter, four-number format. STD meant everyone needed lettered dials for dialing. This became obsolete with all-digit numbering in 1968.

Intercepted Number

In mid-20th century North America, if a call couldn’t be completed, an intercept operator would tell you why. By the 1970s, this became automatic intercept message systems. Disconnected numbers get recycled, of course.

Outside North America, operator intercept was rare. In most places, you got an automated message or a tone. Some networks use a Special Information Tone (SIT) before the message. It signals an error, useful in multilingual situations.

Modern telephone keypads have "*" and "#". They’re not just for show.

Special Feature Codes

These special service codes, like vertical service codes, use symbols like the star (*) and number sign (#). They enable or disable telephony services. The number sign often signals the end of a sequence, preventing delays.

In Popular Culture

Fictional numbers are used in films and TV to avoid bothering real people. The US 555 exchange was mostly reserved. Bruce Almighty used 776-2323, but the DVD changed it to a 555 number. Turns out, the original number did exist in Buffalo, NY, causing some people to get calls from people asking for God. Annoying, I’m sure.

The Glenn Miller Orchestra's song "Pennsylvania 6-5000" refers to the Hotel Pennsylvania in New York City. That number, now 1-212-736-5000, is supposedly New York's oldest continuously assigned number.

Australian films and TV? No standard for fictional numbers. The 555 code exists there, but numbering systems have changed.

And then there's "867-5309/Jenny" by Tommy Tutone. That song caused a lot of unwanted calls to people who actually had that number. Poor souls.

See Also