John Pazmin-o
 NYSkies Astronomy Inc
 2017 May 3

 On 1 May 2017 TR&T and Verizon advised that a new, the seventh, 
telephone area code will start up in New York City. it is '332', to 
open on 10 June 2017. All new NYC phone nymbers will be assigned 
within it without disturbing current phone numbers. 
    Readers remember several previous area codes for the Citym such as 
the first new one back in 1984, '718'. A few readers remember when 
area code '212' first allowed directy dialing long-distance calls in 
the mid 1960s. 
    Before then LD calls were requested thru the AT&T switchvoard 
operator, obtained by dialing '0'. She -- operators were almost all 
women in those years -- manually wired her switchboard to tie the 
remote phone to the caller's phone. Occasionally she explained this 
task will take a while and offered to call back when the connections 
were lined up.
    Because of the manual involvement, a LD call was costly. In many 
businesses an employee had to get prior permission before placing a LD 
call in the course of duty.  Commonly a person treated a received LD 
cal with special attention, perhaps an emergency or assignment. 
    I compile here a history of telephone area codes for the City.   
It is assembled from various sources in the web and ancient paper 
material.  Because it seems that news area codes will continue to add 
to those already in New York City, all discussion here is addiurnate 
only as at mid 2017. 
Origin of area codes 
   During World War II AT&T's Bell Labs invented a mechanism to 
automaticly connect a calling phone to its receiving phone across 
local calling zones, a long-distance connection,  without intricate 
hook-up by the operator. Until then when an operator got a long-
distance request she connected her switchboard in a chain from the 
caller to the receiver. 
    The new method mapped the United States into zones, each with a 
three-digit number. This number was a prefix to the receiver's phone 
    The caller still asked the operator for the LD call, but now she  
keyed in the appropriate prefix on her switchboard. This did away with 
the tedium of hand-wiring the connection. The prefix was only for 
internal AT&T use. The LD caller did not know about ut. 
     The original set of prefixes started yp in 1947 October 1 with 86 
zones in the US. For technical and historical reasons the scheme 
covered also Canada, Quebec, and British islands in the Atlantic and 
Caribbean. The original numbering scheme was called the North American 
Numbering Plan, NANP. Over the next decades the plan was extended to 
other Caribbean islands, US overseas territories, and Alaska & Hawaii 
when they entered statehood.
    The zones were officially called Numbering Plan Areas, NPA, each 
with a NPA code. Almost immediately the name was shortened to 'area 
code' or AC. 
    When AT&T was diffracted in the 1980s the US FCC arranged the NANP 
system into a separate company, the North American Numbering Plan 

Direct Distance Dialing
    The ultimate purpose of area codes was to let callers directly 
dial LD phones. Such a system eliminates the burden on the switchboard 
operator and opens LD calling as a more casual and spontaneous 
service. Testing of caller-initiated LD calls, Direct Distance Dialing, 
began on 1951 November 10 between Englewood NJ and Alameda CA. AT&T 
arranged for the mayors of these towns converse by Englewood dialing 
Alameda with the area code method. 
    Tests of the new system, Direct Distance Dialing, DDD, continues 
thru the 1950s. During these tests a prototype dialing method was 
installed between New York City and New Jersey. A caller in the City 
could directly reach a phone in New Jersey by dialing 1 plus the New 
Jersey phone number. Only certain exchanges in northern New 
Jersey,were hooked up into this program. A New Jersey caller, in one 
of these particular exchanges, could reach a City phone by dialing 11 
plus the City phone number. Both sets of phones were in the then 
hidden area codes 201 (NJ) and 212 (NYC). 
    Direct Distance Dialing spread gradually in the 1950s thruout the 
US, at first in the larger metropolitan regions. That's when area 
codes were released for caller use, as the necessary prefix for 
dialing long distance calls.                                 
     Every so often AT&T bannered the addition of more towns or states 
and a map of area codes in the company's phone book ws slowly filled 
in with DDD-accessible regions. 

Numbering scheme 
    The area code number was a simple logical, almost elegant, system. 
An early map of the area code zones was actually a quite attractive 
graphic. No one could imagine that before the 20th century was over 
this nitid plan would fall apart.  
    A whole state was given a code with middle digit 0. A portion of a 
state, typicly large towns and metropolitan areas, got a prefix with 
middle digit 1. The map had a single x0y code for entire states and a 
bunch of x1y codes for partitioned states. A state did not have both 
x0y and x1y codes. 
    New York State had the most partitions, five, each with its own 
x1y code. The next greatest number of codes, four, went to Illinois, 
Ohio, Pennsylvania, and Texas. 
    The x, first, digit was assigned from the volume of telephone 
traffic in each area. The volume of traffic was binned into eight 
ranges, 2 thru 9, with 2 for the highest and 9 for the lowest. 0 and 1 
were invalid values for the x place in the code. 
    The logic behind the x value was that calls to high traffic zones 
should need a short-dial, short stroke of the finger in the 
telephone's rotary dial. A low traffic LD call could live with a long-
dial, longer arc on the dial. 
    The y, third, digit was simply the order of the code in each bin 
of x values. Number 0 was not allowed in y place of a x0y code and 
both 0 and 1 were avoided in a x1y code. 
     This NANP provided for 152 area codes, of which 86 were initially  
used. The remaining ones were salted away with no certain idea what to 
do with them. 
    The first whole-state area code was assigned to New Jersey, home 
of Bell labs, 201. The first partial-state code was given to New York 
City, 212. 

    By World War II AT&T phone numbers stabilized at a 7-character 
form. The first three were the exchange, a trunk line homed at one of 
AT&T's  dispatching depots or exchange houses. The last four were the 
line or station number, 9,999 per exchange. Line '0000' was reserved, 
not issued to customers. A dispatching depot could work tens of 
exchanges, trunk lines, handling myriads of phone numbers. 
    The exchange was named for a geographic or historical word 
associated with the exchange house, The first two letters of this name 
were the first two chars of the exchange. The third place was a digit 
chosen to avoid conflict with other exchange names with the same two 
initial chars. 
    The usual way to state a phone number was two alphas and one digit 
for the exchange, then a hyphen, and then four digits for the line, 
such as CO4-1164 for the 1164th line in the COrtlandt exchange. 
    An inspection of the telephone dial, or keypad on today's phones, 
reveals that the 0 and 1 spot have no alphas attached to them. Because 
an exchange starts with two letters, an exchange can not have 0 or 1 
in its first or second place.  These places may have numbers 2 thru 9, 
standing for alphass attached to them. 
    The telephone network needed a means to recognize that the initial 
chars dialed into it was an area code for a LD call and not an 
exchange for a local call. The solution was to make the middle digit 
of the area code a 0 or 1, distinguishing it from an exchange. 

Some restrictions
    Certain combinations of area code digits were reserved for special 
functions, not as a prefix for LD calls. Codes x11 were complete phone 
numbers, like 911 for emergency medical and rescue services and, for 
New York City, 311 for municipal agencies. 
    x00 codes are whole-country LD prefixes, not confined to a 
specific region. 800 is for free-call numbers where the recipient pays 
the phone charges. 900 is for pay-calls where the recipient charges a 
fee on top of the phone company charge. 
    x10 codes were mostly unused but 710 was for nation-wide teletype 
service. This is by the 21st century about dead, freeing this code for 
other uses. 
    Area codes can not start with 0 or 1 due to technical imitations 
in the telephone apparatus. The first digit is 2 thru 9. 

New aera codes 
    The 1947 NANP made 152 area codes. Under its formula the code 
may have 2-9 in the first digit, 0 or 1 in th 2nd, and 0-9 in the 3rd. 
Codes x00 and x10 were for special services. Codes x11 were not used, 
being complete phone numbers by themselfs. Subtracting all 8 of these 
leaves (8 x 2 x 10) - 8 = 152 codes. 86 were enough to fill out the 
United States and certain adjacent countries. The unused codes were 
put away with no clear need for them. 
    By the 1970s some areas were running out of open phones, like in 
New York City. Its 212 area was rapidly filling up, mostly from newly 
installed data networks and direct dialing to individual business 
phones. A new cause for the swelling demand for phones was the special 
services offered by the new non-AT&T telephone companies, each 
requiring access to ample stocks  of phone numbers for their own 
    The way to generate a supply of new open phone numbers was to 
create a new area code. Each code controls its own full stock of 
phones, separate from those of existing codes.
   At first new area codes came from the unused original ones. To 
avail of these open codes the nitid scheme of whole/partial star and 
telephone traffic was jettisoned.  Any handy code was put in place in 
the required area. Unused codes of form x10 were taken for new areas. 
710, originally for teletype, was released into the pool of open 
codes. Within five or so years some states were covered by a mix of 
x0y and x1y codes. 
     NANPA, created from the former AT&T in 1984, revised the code 
rules to allow almost any combination of digits. The code still may 
not start with 0 or 1. The 2nd digit may be 0 thru 8, missing out 9., 
to have a small reserve of codes for internal use with the same 
exclusion of x11 codes, there now are (8 x 9 x 10) - 8 = 712 codes. 
    The 800 code for nation-wide free-call phones was extended by 
allowing new 8xx codes for this function. 811 and 899 were held back, 
leaving now 8 free-call area codes. 

    An area code can be added to an existing region by a split or an 
overlay. In a split the original zone is divided geographicly into two 
parts. One part keeps the original code. The other takes on the new 
    Telephones in each part remain the same but hose in the new part 
are prefixed with the new code. The ones in the original part keep 
their old prefix.
    The split generates a pool of new phones by segregating the old 
set of phones in the region into two partially-full sets. A phone is 
one part now is a hole in the other, open for assignment. This pool is 
supplemental to the main pool of open phones in the original area, 
which was depleting already with the attachment of new phones. 
    It was a common practice in AT&T to allow callers in both areas to 
continue dialing just the 7-digit phone number, as if they were still 
in one code. This favor, called 'permissive dialing', works as long as 
there are no phones duplicated across the two areas. Instantly holes 
in one area are filling up with new phones, these new phones duplicate 
existing phones in the other area. At that moment, even tho not 
mandatory, it is necessary to include the area code when calling these 
duplicated phones. 
    After several year every one in each region knew enough duplicated 
phones to start dialing the area code on his own. 

    In an overlay the new code is geographic coterminous with one or 
more adjacent regions with old codes. No existing phones are altered. 
They stay within their old area code. The new code is filled only with 
brand-new phones, making good of the code's initially empty capacity. 
Some early overlays were dedicated to new services such as mobile or 
novocal devices. Others were for any new device, even vocal phones. 
    In an overlay the area code must be part of the dialing into it 
because there is no legacy to allow its omission. This is why so 
prevalently mobile devices require thee area code for all dialing, 
even when it's still only optional in the original region. 
    Where there are both a split and an overlay in a geographic region, 
callers may juggle their dialing practices between optional area code 
for numbers that undergoed the split and required code for the new 
numbers in the overlay. Many callers simply took to the use of area 
code for all dialing.

Grace period
    When it is possible to stay with 7-digit dialing across two areas, 
the phone company usually leaves callers alone for some grace period.  
It reminds about the two codes and urges getting used to dialing with 
them, but doesn't enforce the new dialing regimen. 
    In New York, and likely else where, there was a claim of unfair 
competition by the non-AT&T phone companies. They, by the equipment 
they built, required ten-digit dialing for all phones, mobile and 
landline, while AT*T allowed seven-digit dialing for calls within an 
area code. I can't recall active promotion of seven-digit dialing by 
AT&T. It was just the way the company set up its network.T A&T argued 
that its grace period was only temporary and would soon end. Then 
after all numbers will require dialing with the area code. 
    Eventually, often with the addition of an other new code, it's 
time to move to dialing all ten digits, three for the area code and 
seven for the phone. After the mandatory 10-digit dialing takes 
effect, a misdial triggers a phone company greeting to hang up and 
dial again with the area code. 

The 1980s
    On 1984 January 8, by Federal anti-trust action, AT&T broke apart 
into about a dozen independent separate companies. Some were 
designated for local phone service, the 'Baby Bells'. Others handled 
other services such as long-distance calls. In addition, new non-AT&T 
phone companies started up to offer service in competition against the 
Baby Bells. 
    To provide phone service there new companies needed access to open 
phone numbers. AT&T had to let these companies rent phone numbers but 
there was a problem. The electromechanical circuits still prevalent in 
AT&T restricted new phone numbers to a whole exchange. An exchange 
handles 10,000 phones, even if the renting company didn't want so 
many. Since the existing exchanges could mot be broken apart, there 
suddenly was a need to create brand-new exchanges. 
    An other development was that AT&T was moving off of 
electromechanical networks to electronic ones. The newly emerging 
companies started with electronic networks. The electronic system 
reduced the constraints on making new  exchanges and area codes. 
    There was the beginning of widespread mobile phone service, where 
often each person in a household had his own phone, and the rise of 
data phones for the new home computers. These were extra phones in a 
household to avoid hogging the vocal phone when transpiring data thru 
the computer.  
    The diffraction of AT&T span off its North American Numbering Plan 
to a new outfit, NANP Administration, NANPA. At first Lockheed Martin, 
aerospace company in Colorado, ran it. Since then other firms took up 
the service with the present contract expiring later in 2017. 
    NANPA's immediate first task was to work up new rules for new  
codes and exchanges. 

New exchanges 
    A traditional exchange was formed from a name associated with the 
territory of its dispatching center. The first two chars were the 
first two letters of the name. The earliest exchanges had as its third 
char a digit corresponding to the third letter of the name. It soon 
became impractical to hold to this rule and the third char is really a 
conflict-breaker among exchanges with the same two initial letters. 
    In New York AT&T started to wean people from the exchange names 
and move them toward an all-digit scheme. For example, the exchange 
COrtlandt4 was cited as 264. New Yorkers didn't take easily to losing 
their names! 
    When I was at school AT&T relabeled its public pay phones on the City 
College campus  with the all-digit phone numbers. Students made new 
labels with the old AUdubon exchange name and carefully inserted them 
into the dial plate of the pay phones. They stayed in place until the 
next occasion that the phone was visited by AT&T maintenance crew. A 
similar tactic was carried out for the MOrningside exchange at 
Columbia University. 
    There is one concession that I know of. In 1960 two airliners, one 
just after taking off from LaGuardia andd Idelwild (not yet renamed 
Kennedy) airport, collided over Brooklyn. Wreckage rained down  
centered over Sterling Street. The accident is still sometimes called 
the Sterling Street disaster. The district is in the STeerling 
exchange. AT&T, in memory of the accident, never tried to push off the 
name for this exchange. over the following decades, as phone numbers 
are removed and new ones added, the STerling exchange is fading into 
    As charming and romantic as the exchange names were, thru 
constrained the full capacity of an area code. Many valid letter-digit 
combination were not  used simply from want of a name for them. 
Granted, some names seemed whimsical, like for my late ladylove at 
BUtterrfield; an astronomy club at LEhigh. the natural history museum 
at TRafalgar; friends at NIghtingale, TUlip, DIgby, REgemts, 
TEmpleton, HYacinth, IVanhoe, ... . Even so, the capacity of an area 
code, with all its working exchanges, was more like 5 to 6 million, 
not  the maximum capacity of 7.9 million, phones. 
    NANPA opened exchanges to all combinations of digits, with a few 
simple exceptions. The exchange may not start with 0 or 1. Exchanges 
of form x11 still were reserved for complete phone numbers. The 
number of exchanges is now maxed out at 792. This is (8 x 10 x 10) - 
(8 x11 numbers) = 792. 
    All brand-new exchanges are nameless. They are all-digit from the 
start. While a name can be forced into the digits it is not 
recognized by any phone service.
    Each exchange can handle 9,999 phones, not 10 thousand because 
line number 0000 is for internal use. The full count of phones per 
area code is 792 x 9999 = 7,919,000. 

Names come back!
    It seemed that with the detachment of exchanges from names, and 
all-digit dialing was the norm by the 1990s. telephones will son drop 
letters from their dials and keypads.
    But a new telephone service forced the letters to stay in place! 
     The non-AT&T companies offered vanity phone numbers, those whose 
letter-equivalent spelled a word. This was typicly the name of the 
customer or its product or service. The customer could ask for such a 
number and, if it was still open, it was assigned to him. The customer 
advertised the number as the word, like PILLOWS.
     The classical dial and early keypads carried on each number three 
letters, with 0 and 1 skipped. The same set of digits could spell out 
several desired vanity words. There was a battle, with lawsuits, to 
get hold of desired vanity number. 
    The 8 keys (2-9) with 3 letters each covered 24 letters. Since the 
English alphabet has 26 letters,  Q and Z were skipped. AT&T avoided 
exchange names with these letters in the first or second place. 
    The absence of Q and Z made for fictitious exchange names, like 
for movies or comics. A phone number in a film may be OZone2-3456, 
with assurance that it could not conflict with a real phone. 
    When dialing a vanity phone, the telephone network 'sees' only the 
digits corresponding to the letters. Also, once 7 digits were dialed, 
the call was processed, even if more digits were sent out. This feature 
allowed longer vanity names because only the first seven chars were 
recognized. To some degree this alleviated the fight to capturing a 
vanity number fitting into seven chars.  
    By the mid 1990s  there was no longer a need to avoid Q and Z in 
a vanity name. Only digits were sent to the phone grid. Newer 
telephones were built with keypads carrying all 26 letters. The 7 key 
has PQRS; 9  key, WXYZ. Vanity names like QUALITY and ZIG2ZAG could be 
    The need to include Q and Z in dialing was also driven by some 
robot greetings for businesses. They ask to key in the name of the 
desired person, department, service. The name could easily require the 
letters Q and Z. To handle callers with classical keypads, the 
greeting may note that for Q and Z key in 7 or 9. 

1-Plus dialing 
    Ten-digit dialing helped prevent misdialing duplicate numbers in 
split areas.. This practice was fine when the switching center could 
tell that the first three digits were in fact an area code and not a 
local exchange. That's what the 0/1 in the second place of an area 
code was for since no exchange could have 0 or 1 in that place. 
    When the new codes, made of almost all combinations of digits, 
were introduced the area code looked like an exchange. There had to 
be a way to alert the circuits that the stream of digits dialed started 
with an area code. The solution was to add a new prefix, number 1, for 
all dialing. The circuits sees this initial 1 and know the next three 
are the area code, followed by the 7-digit local phone number. This 
was known as '1-plus' or 'all-11' dialing. 
    Depending on the region, this dialing regimen was a shift from an 
existing ten-digit dialing or was already the dialing scheme even the 
expiration of a grace period. New York City went to 1-plus dialing when 
its permissive dialing expired on 2003 February 4. The City did not 
have a mandatory 10-digit system only an optional one.
    Calls dialed with only 7-digits triggered a phone company greeting 
to hang up and dial '1 plus area code and the phone number'. 
    Mobile phones and certain novocal devices may skip the 1 prefix, 
leaving it as an option. This results from the particular phone 
service being built up with 10-digit dialing. Since their equipment 
recognized the sequence of numbers already, there was no need to 
impose an extra prefix. 

AC 212
    New York City got its first area code on 1947 October 1 as one of 
the initial86 codes set up by AT&T. For over a decade it was an 
internal function of the switchboard operators. LD dialing by the 
caller started on 1951 November 10 in area 201, New jErsey, as a test 
run by Bell Labs. After a few years of more testing LD dialing opened 
for caller use across the country starting in the mid 1950s. 
    Beginning in 1960 select exchanges in the City were opened for 
Direct Distance Dialing. Direct Distance Dialing was highlighted at 
the AT&T pavilion of the New York World's Fair. More exchanges were 
hooked up until by 1965 the whole City enjoyed Direct Distance 
    Adjacent sections of the City region got their own codes, also on 
1947 October 1: 516 for Long Island, 201 for New Jersey, 203 for 
Connecticut, 914 for nearby upstate. 
    To call phones within the 212 area, only the7-digit phone number 
was dialed. The area code was entered only for calling to other codes. 

AC 718 
    The City's 212 area was split on 1984 September 1 into 212 and 718 
codes. 212 stayed on Manhattan and in the Bronx. 718 covered Brooklyn, 
Queens, Staten Island. Optional 10-digit dialing prevailed until 2003 
February 1, when it was replaced by compulsory 1-plus dialing. There 
was no compulsory 10-digit dialing for the City, as it was phased out 
within the optional-area-code grace period. 
    Besides the very island of Manhattan, certain off-shore islands 
associated with Manhattan stayed in 212. These include Liberty & 
Ellis, Belmont (now U Thant), Governors, and Roosevelt. 
    On 1992 February 4 the Bronx was moved into 718 area to free up 
phones for the rapidly-growing 212 area. This was also when new code 
917 came on line. 
    The former 212 phones of the Bronx were now holes in 212 ready to 
fill with new 212 phones. Eventually these 212 numbers duplicated the 
Bronx 718 numbers. This situation started the long period of having to 
dial 10 digits for certain phones and only 7 for others. 
    The incidence of a duplicate phone number comes with no notice and 
spawns some hysterical episodes. In New York an astronomer in new area 
718 on Staten Island suddenly got several calls per day for a bank's 
customer office. The bank was in area 212 on Manhattan and moved its 
customer office. It acquired a set of new phone numbers, one 
duplicating the astronomer's. 
    The bank's advertising and publicity still showed the 7-digit 
number, as it did for the indefinite past.  Callers looked up the 
number and dialed it. If the caller was in 212 area the call went thru 
correctly. If in 718 the caller rang up the astronomer. 
    The astronomer revised the greeting on her anserfone to warn that 
to reach this bank the caller must hang up and dial again with the 212 
prefix. This reduced the influx of wrong calls but the couple per day 
was still irritating. 
    The astronomer came up with a plot that was reasonable in the 
1980s but is not recommended in today's climate of ID theft and 
information hacking. 
    She pretended to be the bank! 
    She worked in business and know the lingo of finance and banking. 
She politely spoke with the caller, wrote down his details, and 
assured that the inquiry will be handled within ten days or so.  
    After collecting five or six callers, she did up a business letter 
to the bank's manager with the caller information. She hinted that the 
bank may have other phones duplicated between 212 and 718 and, hmmm, 
what happens to the caller information disclosed at those phones? 
    Within a week the bank revamped its litterature and ads to include 
212 with its phone numbers. 

Marble Hill
    Marble Hill was a paeninsula at the northern ti The name probably 
comes from the exposure of native Inwood marble, occasionally mined for 
building stone. p of Manhattan. The Harlem River wrapped around it in 
a hair-pin curve. 
    The sharp tight bend in Harlem River by the late 19th century grew 
into  a hazard to shipping. In 1895 the City arranged to have the 
paeninsula cut off, roughly in line with the adjacent Manhattan 
shoreline, to make a straight path for navigation. The old water 
course was filled in and opened for development. 
    The formal legal definition of 'Manhattan' included the far, Bronx 
side, shore of Harlem River as it existed in colonial time. The line 
followed the hair-pin loop. This boundary line was never updated after 
Marble Hill was severed fro Manhattan and attached to the Bronx! 
Residents and business on the hill are 'on Manhattan'. The Bronx 
treats them as part of Manhattan-occupied territory. Every president 
of the Bronx puts out the goal of taking back the 'Sudetenland' of 
Marble Hill. 
    Truly riotous episodes erupt over the decades. One is a school 
that was built in the filled-in zone, straddling the Manhattan-Bronx 
border. it flies the Manhattan flag on one side  of the building and 
the Bronx flag on the other side. 
    When telephone service was set up in the Bronx it was natural to 
wire up Marble Hill into the network of the Bronx and not string wires 
across or under Harlem River to the Manhattan phone grid. This was no 
problem since either there was no area code system or there was the 
one 212 code for the entire City. 
    When the Bronx shifted into 718 area, Marble Hill went with it! 
Ever since then Marble Hill takes on all the changes in phone service 
as the rest of the Bronx. 

AC 917
    On 1992 February 4 code 917 was installed as an overlay on both 
212 and 718 area, all over the whole City. It was just about the last 
of the original codes left and was reserved at first for mobile and 
nonvocal phones. Existing mobile/nonvocal phones were moved from 
212/718 into 917. Because this was a different code, like in an other 
town, 10-digit dialing was required. At the same time the Bronx was 
shifted from 212 area into 718. 212 now covers only [most of] 
    Mobile phones aren't tied to a specific territory. They may do a 
call from any where in the country. Mobile phone systems wee built to 
require 10-digit dialing for all calls, even those within the 917 
area. When 1-plus dialing began, it did not apply to most mobile 
phones. The initial 1 was tossed and the remaining ten digits were 
    In the mid 1990s the US FCC banned new codes for specific services 
but grandfathered 917.  As it happened, new codes were opened that 
handled mobile phones. Leftover open phones in 917 were issued to any 
type of new phone. 

AC 646 
    Code 646 opened as an overlay of 212 on 1999 July 1 to handle 
phones spilling over 212's capacity. There just were almost no open 
phones in 212. Many new phones were mobile phones, a service was 
exploding in the late 1990s, causing some people to think 646 is a 
dedicated mobile phone code.  it was merely the case that most new 
phones were mobile, not landline, phones. 
    Altho there are by now absolutely no open phones left in 212 it is 
possible to obtain a new 212 phone number! As homes and businesses 
move they take on new phone numbers in the newer codes. The old 212 
numbers are turned back to the phone company.
    Firms sprang up to watch for released 212 numbers and sign up for 
them. Usually they come in blocks, like for a business with many 212 
phones. The phone 'broker' sells these numbers, for this mother of all 
codes, to new customer. 
    When signing up for mobile phone service, a contact phone is asked 
for customer service calls. If the offered number is in 212 area the 
mobile phone is tied to the 646 code. A 718 number puts its mobile 
phone in the other new code 347.

AC 347
    Code 347 overlays 718 and started on 1999 October 1. Like 646 it 
handles new phones spilling from 718. Its growth is not as rapid as 
for 646 but in the 2-thous the rate of new hookups ramped up. This is 
probably due to the massive influx of data-intensive companies into 
Brooklyn and Queens. Like for 646 a mobile phone is given a 347 number 
for a contact phone in 718. 

AC 929 
    This is an overlay of an overlay! I929 started on 2001 April 16. 
It sits on 917 area, which was starting to exhaust its remaining open 
numbers. New phones go into 929 while existing 917 phones are not

1-plus dialing

AC 332 
    Code 332 starts on 2017 June 10 as an overlay of 212/646. As 646 
phone numbers are used up, new phones are given 332 numbers. Current 
phones are left alone. 

    Most people have no inkling of how and why the telephone works. 
They key in a bunch of digits and, presto!, they're talking to an 
other person tens, hundreds, thousands of kilometers away as clearly 
as if that person was by their side. It took more than six decades to 
hammer out the long-distance area code system and to expand it to 
keep up with the swelling demand for new phones.
    If all seven of New York's area codes fill up to their capacity of 
7.9 million numbers, the City would be handling over 55 million 
phones! This is probably all the telephones in the entire United States 
when the North American Numbering Plan started in 1947. 
    A parallel development was the hook-up of telephones in New York. 
Considering only the hard-wired phones, not wireless ones, AT&T and 
partner Verizon estimate that the length of telephone wire placed in 
New York (whole city) is about 60 million kilometers! This is the 
distance from Earth to Mars at the  2018 opposition