When NYC got overlay codes ( back in around 2000) 11 digit dialing ( we have to dial the “1” from landlines even for local calls ) was required by the FCC. From what I remember, it was because businesses somehow feared that they would lose business if a customer calling from a 718 number had to dial eleven digits to call a pizzeria with a 347 area code but only seven to dial a 718 number. Apparently, they were afraid the customer would call a business with a 718 area code to avoid the extra digits. Which sounds ridiculous , but I know people who went crazy trying to get a cell number with a 212 or 718 area code rather than 917.
Welcome to the 21st century!
DC metro area here. When we first moved here, the 3 local area codes were 703 (VA), 202 (DC) and 301 (MD). We could dial any phone number in the 3 areas with just 7 digits. Of course it could be a pain to figure out which 703 numbers were local and which were not (i.e. required a 1 in front, e.g. 1-703-555-1212). There was a map of some sort in the front of the phone book (anyone remember those?) which was of some help.
I imagine there was some sort of agreement where an exchange (the ‘555’ part of that fake number) was limited to one of those 3 areas - though I don’t honestly know whether that also extended to outlying places in the same area code, but not “local”.
Local places would often abbreviate the area code by just putting the last digit, though you had to actually dial the whole thing - e.g. 703-555-1212 would be written as 3-555-1212 while 202-666-1313 would be written as 2-666-1313. Fortunately that did not last long.
All in all I kind of welcomed the combination of 10 digit dialing, and the concept of long-distance calls becoming essentially meaningless, The overlay area codes are a minor annoyance: 571 is our overlay, and my in-laws live in 561 (Florida) which often confuses me :). And of course I sort of knew most of the old-style area codes, but nowadays I don’t readily recognize where a call comes from anymore.
Area codes in general are far less meaningful in telling you where the person is from, given the preponderance of cell phones and keeping the same number when you move elsewhere. I just started a project based in another timezone; talking to my new team lead, I was surprised to see he had a local-to-me area code (REALLY local - turns out he grew up about a mile away from me and went to the same high school my kids did). My daughter lives 500 miles away and still has our area code (her phone is on our family plan).
Neighbor!! (sort of… we’re in the other suburban state). Yeah, when you get a new cell phone you can request it be assigned to an area code. When we first got prepaids for the kids, 14 years or so ago, we got them from T-Mobile and the “regular” area code (703) was not even an option, we had to go with 571. I assumed this meant that they were out of 703 numbers.
A few years later, when we added Dweezil to the family plan (going off to college, we no longer wanted him to be on the prepaid plan) on Verizon, they gave him a 703 number, no quibbles. So maybe T-Mobile only had access to the 571 area code or something. When we moved Moon Unit to the family plan a couple years after that, we could have given her a 703 number as well - in fact, might have been easier; the Veridiots claimed they could not reliably port that number over because “reasons” (they managed to do it - I think by briefly adding a line of service to our account or something odd).
I wonder how many decades it’ll be before the first 3 digits ceases to be meaningful at all. Right now it still has a pretty strong geographical connotation but with people being so mobile, there’s more and more of a mix in my contacts list.
I don’t know of any other 3 digit numbers that were set aside in that fashion. Even the 555 exchange is in use. For instance, in @Mama_Zappa 's post, she uses a 555 number thinking that it was a generic fake number, but it actually is someone’s real phone number.
If there were some set aside for a use, then they are in use for that purpose.
I wonder how long it will be before telephone numbers themselves are at best a legacy, and the vast majority of telecommunications runs over tcp/ip.
Back in the day, the “1” was a sign that it was a toll call. That fell apart with the Bell breakup, I suspect.
We still have seven-digit dialing here, thank God. My parents and one of my sisters, in a different adjoining area code, have to dial eleven digits just to call a house across the street. What a pain in the ass!
Did you call it? Why do you think that’s a real number? Googling that shows it to be on a list of robocallers, but that doesn’t mean it’s a real number. They spoof numbers all the time so what shows up on the Caller ID isn’t actually what called.
This doesn’t really explain anything. We have to prepend 1 to any call outside our local calling area, but not to any inside it. Had they changed it to, "You have to prepend 1 to any call to another area code (including a different code inside our calling area), then they could have allowed us to continue using 7 digit dialing. But they don’t. They seem to want to use the 1 to signal a toll call.
I didn’t call it, that would be rude, but when I googled it, it came up with the name and address of a real person.
Maybe that was not accurate information, but 555 numbers are not all fake, only 555-0100 through 555-0199 are.
10 digit dialing has been a thing in Oregon since forever. My pet peeve is you never know if it’s local or not. So do I dial a 1? or not? I wish it was just universal. It is the bane of my existence to dial a number to have the phone tell me “you must first dial a 1” and as often as not, I dial the 1 and the phone says “do not dial a 1”. If I ever go postal, this will be the reason. Just make 11 digits universal. Or not needed. My cell phone knows how to do it with just the 10 digits. FFS
I think that may only be a POTS thing.
For cell phones or cable based phone, a 1 is never necessary.
(May be necessary for international calling, but not for anything domestic.)
Because POTS doesn’t use any special key to indicate “I’m done dialing” the system has to know how many digits to expect in the number before you finish dialing it.
For example, 972 is an area code in the Dallas area. That could also be an exchange (the 1st 3 digits of the 7-digit number) in your local area code. Maybe not right now, but soon. So you start by dialing 972. How does it know to expect 4 more or 7 more digits? It can’t anymore, so they make you dial all 10.
Hari’s suggestion is that if it starts with a 1, the system will expect 10 digits to follow; otherwise, only 6 more digits.
Alternatively, they could have implemented a timeout. If you punch in only 7 digits, then after a couple seconds it tries that number in the current area code.
They could implement a timeout, but whatever delay they chose, they’d get complaints that it was too short or too long. So they stuck with the existing system of figuring it out based on the earlier already-dialed digits.
I’ve lived in area codes where it was necessary to dial a 1+7 digits for toll calls within the same area code. Yes, it would have made sense to require 10 digits for those, but they didn’t do that. So this is where we are now. There are a lot of things they could have done better as the system developed over decades, but didn’t.
555 numbers are not all fake- but at least some of them are/were reserved for internal phone company use. I instantly recognized (xxx) 555-1212 as the number I would call for directory assistance outside my own area code. There were other 555 numbers for the time and weather.
I am shocked to learn there are places in the US that still only need to dial seven digits. Wow.
I was surprised to learn that pretty much everywhere else already uses 10. 
On the other hand, if you make everyone always dial the extra digits, then whatever prestige is associated with an OG 212 code is always apparent. So the idea that 10-digit dialing somehow puts all businesses on equal grounding might backfire.
Very simple: if you start with a 1, it’s 11 digits; if not it’s 7.
Also, if I mistakenly dial 1-514-… (my code), why bother telling me to redial without the 1? Just put the call through.
You beat us! We’ve had the ten digit dialing in the 310 only since 1999. I HATED it at first, but I adjusted pretty quickly and easily.
Interesting article on the use of the 555 prefix.
You’re right, 555 is now used for real phone numbers. 555-1212 is still a reserved number (directory assistance) and others are still reserved; per the linked article:
The article mentions the old exchange name thing. 555 would have been referred to as KLondike 5 (K and L both being on the 5 key); my number growing up would have been KIngsley-whatever (“54”) though I only ever heard that once or twice - we just read out the full 7 digit number.
Forgot to mention: there is still some loose association with exchanges and geographical areas. When I first got a Google Voice number, I was lucky enough to be able to pick an exchange that was not all that far from where we live (one town down the interstate). You can look these up at DETAILED Telephone Number / Prefix Locations in any Area Code (with maps). I could, of course, have picked almost any area code I liked.