Telephone numbers

[Poiponen13]

Proposed number formats (A=area code, L=local number)
AAAA LLL LLL
AA LL LL LL LL
AL LL LLL
AA LLLL LLLL
AAA LLLL
AAAA LLLLL
AAA LLLLLLL
AA LLL-LL-LL

[kphoger]

(A=area code, L=local number)

AA LL LL LL LL

AA LLLL LLLL

These two formats are commonly used in Mexico's largest metro areas, which have 2-digit area codes.  I've also seen the first one used in places with 3-digit area codes (AA-AL-LL-LL).

Here is a billboard example of AA-LLLL-LLLL from Monterrey, which is area code 81:



And here's an example of AA-LL-LL-LL-LL (but without the area code actually listed, so it's LL-LL-LL-LL instead):



And then there's oddball stuff like this too:


(AAL-LLL-LLLL)


(AALL-LLL-LLL)

[Poiponen13]

Largest cities in US should also have 2-digit are codes and 4-digit central office codes.

[Scott5114]

And here's an example of AA-LL-LL-LL-LL (but without the area code actually listed, so it's LL-LL-LL-LL instead):

This reads like a dotted-quad IP address to me. I probably wouldn't even recognize that as a phone number; I'd probably just get a chuckle out of them being too cheap to buy a domain name and expecting us to remember their website as being http://80.58.7.38 .

Largest cities in US should also have 2-digit are codes and 4-digit central office codes.

I don't want to change my phone number from what it is, though. I've had it since 2007 and I don't want to have to update it on all of my accounts.

So you're going to have to give a reason other than "Should should should should should!"

[kphoger]

This reads like a dotted-quad IP address to me. I probably wouldn't even recognize that as a phone number; I'd probably just get a chuckle out of them being too cheap to buy a domain name and expecting us to remember their website as being http://80.58.7.38 .

The two-digit grouping, with dots or periods in between, is so common in Mexico, that you'd probably get used to it awfully fast.

I briefly tried it about fifteen years ago, when I had a cell phone number of (630) 677-6699.  I tried telling people my phone number as 63.06.77.66.99.  They didn't like it.

(Don't try calling that number.  It isn't mine anymore.  Apparently, it now belongs to a realtor in Naperville.)

[Scott5114]

I wouldn't like it either. It's way easier for me to remember three numbers (630, 677, and 6699) than it would be five. By the time you said 99, the 63 would have fallen out of my head.

[MikeTheActuary]

Hmmm...  It occurs to me that there's a whole department at my company with 'PCS' in its name.  Nobody in the office today knows what it stands for.  I wonder if it's related.  Guess I'll have to ask someone in that department next time I see one of them.

Thinking about some old discussions and as a pretty wild guess... Those PCS (personal communication services) may go to devices which need a cellular data connection, but don't need an explicitly assigned number and more so no number in the area where they are used.  Kindle, Apple tag, tablets...

My wife's cardiac pacemaker monitor is another example.

Additional information:

Non-geographic Services: Originally, area code 500 was intended to be used for "Personal Communications Services"  (a.k.a. "the Other PCS" ), which in this context refers not to cellular telephones, but rather to so-called "follow-me"  numbers. The idea was to have a single number, say ‎(500) 123-4567‎, that you could program to ring your home phone from 6 to 10 p.m., go directly to voicemail at night, and ring your desk at work during the day. The number could also have some sort of response menu, along the lines of "press 1 for voicemail, 2 for fax, 3 for cellphone."  Some implementations also allowed the same 500 number to be used for caller-pays or called-party-pays: dialing ‎1-500-xxx-xxxx‎, the caller would pay the cost of the call, but dialing ‎0-500-xxx-xxxx‎, the caller could enter a 4-digit PIN to charge the call to the owner of the number. However, in spite of efforts to keep telesleaze out of the 500 number space, some unscrupulous operators exploited a feature that allowed 500 numbers to forward internationally, with the additional charge borne by the caller with only a "press 1 to accept"  warning, if that.

"Follow-me"  numbers never really caught on, so the numbering space (including expansion codes 521, 522, 523, 524, 525, 526, 527, 528, 533, 544, 566, 577, and 588) is now used primarily for purposes that require a telephone number but that do not require a number associated with a specific geographic location. In fact, most of these numbers are not dialable on the public telephone network. One example is devices such as iPads equipped to use a cellular data network. For billing purposes, there needs to be a unique number associated with the iPad, even though that number cannot be used for inbound calls to the device. Home alarm systems that connect to a wireless carrier would also qualify. There are also other devices that may not use the phone network at all, but for some reason need a non-geographic telephone number as an address. Area codes 511, 555, and 599 are reserved, so, now that the 522 code has filled up, miscellaneous unused 5XX codes will be used, beginning with 521 and 523 through 529, and then unused 53X codes. Area code 529 went into effect 2022-09-16; area code 532 will go into effect some time in early to mid-2023, followed by 535, probably in late 2023 or early 2024, and 538, a few months after that. The other codes reserved for this purpose are 538, 542, 543, 545, 546, 547, 549, 550, 552, 553, 554, 556, 558, 569, 578, and 589.

Grabbed from: https://lincmad.com/nongeographic.html

[MikeTheActuary]

Largest cities in US should also have 2-digit are codes and 4-digit central office codes.

Given number portability, VOIPs, and the gradual end of 7-digit dialing, some thought really should be given to ending attempts to link specific phone numbers to geography.

The VOIP phone sitting next to me has 4 phone lines.   The phone numbers on those lines are:
+1 678 aaa-bbbb
+1 901 ccc-dddd
+1 438 eee-ffff
+44 028 gggg hhhh

....and I'm sitting in Connecticut (area codes 860/975). 

[kalvado]

Largest cities in US should also have 2-digit are codes and 4-digit central office codes.

Given number portability, VOIPs, and the gradual end of 7-digit dialing, some thought really should be given to ending attempts to link specific phone numbers to geography.

The VOIP phone sitting next to me has 4 phone lines.   The phone numbers on those lines are:
+1 678 aaa-bbbb
+1 901 ccc-dddd
+1 438 eee-ffff
+44 028 gggg hhhh

....and I'm sitting in Connecticut (area codes 860/975).

There are 2 layers here, I would say. First is physical call routing, second in memorizing/dialing. These are well separated in modern internet (few of us would care that www.aaroads.com is actually resolved to 74.208.236.26), but PEnnsylvania 6-5000 is as far as it went in phone dialing. Well, again - most cell phones don't expose you to numbers when a known recipient is called/calling.
But I still assume that if I dial your +44 number from upstate NY, initial connection would go through London; and I wonder if systems are smart enough not to route entire call through UK anyway. Fiber capacity of modern internet is such that all the calls are just a drop in overall traffic, so people may not care enough. It may introduce noticeable delays, though...

[kphoger]

Hmmm...  It occurs to me that there's a whole department at my company with 'PCS' in its name.  Nobody in the office today knows what it stands for.  I wonder if it's related.  Guess I'll have to ask someone in that department next time I see one of them.

So I just asked.  And no, they called their department 'PCS' shortly before Personal Communication Services became widespread (but I think it had to have been after Sprint PCS launched in the mid-90s).  I wasn't sure if they utilized that technology in their lottery installation projects, but nope.

I asked them anyway, however, if they know how VoIP calls are routed.  All of them seemed pretty confident that international VoIP calls are not routed like traditional international calls.  That is, their understanding is that, if I make a VoIP call to a +44 number in Connecticut from my desk in Kansas, it's really no different from me sending you an e-mail to a .co.uk account and you just receiving it in Connecticut.  But that now makes me wonder...  My desk phone is VoIP, but what if I were dialing from a traditional landline phone?

[kphoger]

I'm not sure how many of you have heard of ChatGPT, but it's a new chatbot that can create good user essays, write better Star Wars Episodes X-XII than the actual creators can do VII-IX, and a lot more. It contains data up to 2021. However, you cannot rely on it for accuracy. I want to know if the model used any of this forum for training. You will need to create an OpenAI account to use the bot though. Note that you cannot mess up the bot permanently, as it does not learn from user input, which is necessary as previous bots have typically been taken over by Neo-Nazis. This post was written by a human, trust me.

I asked them anyway, however, if they know how VoIP calls are routed.  All of them seemed pretty confident that international VoIP calls are not routed like traditional international calls.  That is, their understanding is that, if I make a VoIP call to a +44 number in Connecticut from my desk in Kansas, it's really no different from me sending you an e-mail to a .co.uk account and you just receiving it in Connecticut.  But that now makes me wonder...  My desk phone is VoIP, but what if I were dialing from a traditional landline phone?

The company CEO put my question into ChatGPT.  Here is what it returned:

When using VoIP to make a call from the US to the UK, the call does not necessarily have to route through the UK.  With VoIP, voice and other multimedia communication is transmitted over the internet, rather than over traditional phone lines.  This means that the call can be routed through any internet connection, regardless of the caller and the recipient.

However, it is possible for the call to be routed through the UK if that is the most efficient or cost-effective route.  The exact route that the call takes will depend on various factors, including the specific VoIP provider being used, the location of the caller and recipient, and the availability of internet connections along the way.

[...]

To make a call from a landline to a VoIP number ... the call will be routed through the phone network to the internet, where it will be delivered to the VoIP provider.  The VoIP provider will then route the call to the intended recipient.

The bolded clause is where the answer lies.  Does the PSTN hand the call over from copper wires to the VoIP SIP protocol before or after it's recognized/routed as an international call to the UK?

[roadman65]

Are there any places that still use seven digit dialing?


In Florida where two area codes share the same territory ten digit is a must as those who set the system says two area codes and seven digits is impossible.

[CtrlAltDel]

There are 2 layers here, I would say. First is physical call routing, second in memorizing/dialing. These are well separated in modern internet (few of us would care that www.aaroads.com is actually resolved to 74.208.236.26)

Just out of idle curiosity, is there a place i could go and type in 74.208.236.26 where it will take me to www.aaroads.com? I thought maybe I could type it in the URL bar of my web browser, but that just gives me a 404 error.

[kphoger]

Are there any places that still use seven digit dialing?

In Florida where two area codes share the same territory ten digit is a must as those who set the system says two area codes and seven digits is impossible.

Obviously, the answer is "where two area codes don't share the same territory".

I can dial my personal cell phone from my VoIP desk phone here at work, using 7-digit dialing, and it rings through just fine.  It only works for local calls, though.  A call to Derby doesn't require dialing (316), but a call to Newton does.  This might be dependent on the LRN for each phone number;  I don't remember if Newton and Wichita are in the same LRN.

[CtrlAltDel]

Are there any places that still use seven digit dialing?

In Florida where two area codes share the same territory ten digit is a must as those who set the system says two area codes and seven digits is impossible.

Obviously, the answer is "where two area codes don't share the same territory".

Not necessarily. For example, as part of the rollout of the 988 emergency suicide number, a number of area codes with no overlays, but with regular phone numbers starting with 988, were changed to require 10-digit dialing to deal with that.

[kphoger]

Right.  Not necessarily.  I'm sure there are plenty of non-overlay areas that require 10-digit dialing.  But the issue described by |roadman65| does not affect those areas.

(By the way, LRN is why you can't always transfer your landline number from one house to the other when you move, even if you move within the same area code or even the same town.  If your move crosses an LRN line, then you can't bring the number with you.  I heard once that there was a medical office in NW Arkansas–which has a bazillion LRNs–that literally moved across the street and had to get all new phone numbers because the new location was in a different LRN.)

[kalvado]

There are 2 layers here, I would say. First is physical call routing, second in memorizing/dialing. These are well separated in modern internet (few of us would care that www.aaroads.com is actually resolved to 74.208.236.26)

Just out of idle curiosity, is there a place i could go and type in 74.208.236.26 where it will take me to www.aaroads.com? I thought maybe I could type it in the URL bar of my web browser, but that just gives me a 404 error.

As far as I understand, the way things work for high volume  providers is there may be many web servers served by the same machine. Once your request is routed to that machine, address from the request is analyzed and request is routed to appropriate software system. Aaroads.net is an extension added to ip address if you will.

[Big John]

Since the implementation of 988, remaining 7-digit calling areas have greatly diminished.

[hbelkins]

Are there any places that still use seven digit dialing?

It was big news in my rural area of Kentucky when landline subscribers had to go from four- or five-digit dialing to seven-digit dialing.

I can still dial local calls on my cell phone using seven digits, sometimes. It's a crapshoot as to whether the call will go through or I'll get a recording that I have to dial the area code, or 1 plus the area code.

[Scott5114]

I just do the whole shebang with 1 and area code on the rare occasion I have to manually dial phone numbers anymore. It's too hard to keep track of what is and isn't allowed to be seven-digit dialed.

I only have five phone numbers memorized: my own, my wife's, and my parents' (their landline and both their cell numbers). I don't even know my best friend's number, which is sometimes confusing because she's had two since I've known her and one goes to a realtor in McAlester now.

[US 89]

I just do the whole shebang with 1 and area code on the rare occasion I have to manually dial phone numbers anymore. It's too hard to keep track of what is and isn't allowed to be seven-digit dialed.

Well, your area has had mandatory 10 digit dialing for about two years now...

[Dirt Roads]

I just do the whole shebang with 1 and area code on the rare occasion I have to manually dial phone numbers anymore. It's too hard to keep track of what is and isn't allowed to be seven-digit dialed.

That brings up a painful memory.  When I first moved to North Carolina, our local Mom-and-Pop telephone company was the only set of exchanges in the Greensboro LATA that stayed in Area Code 919 when the Area Code 336 was created a few years prior.  The Mom-and-Pop worked out a sweet deal for long distance charges with Ma Bell, which upset Bell South.  Dialing eastward, we could still use 7-digit dialing within Area Code 919, except that only the Chapel Hill exchanges were local calls and we had to dial "1" before all the others.  Dialing westward was a much different story, as 10-digit dialing was required for local exchanges (running out to Burlington and Elon).  But if you made the mistake of dialing "1" before the local number, Bell South routed the call over to AT&T who applied the long distance charges.  If you called the Mom-and-Pop, they would work with Ma Bell to drop the charges.  It became such an issue that 7-digit dialing to local exchanges in Area Code 336 was restored.  Until 10-digit dialing was mandated for Area Code 919 a decade later.

[MikeTheActuary]

There are 2 layers here, I would say. First is physical call routing, second in memorizing/dialing. These are well separated in modern internet (few of us would care that www.aaroads.com is actually resolved to 74.208.236.26), but PEnnsylvania 6-5000 is as far as it went in phone dialing. Well, again - most cell phones don't expose you to numbers when a known recipient is called/calling.
But I still assume that if I dial your +44 number from upstate NY, initial connection would go through London; and I wonder if systems are smart enough not to route entire call through UK anyway. Fiber capacity of modern internet is such that all the calls are just a drop in overall traffic, so people may not care enough. It may introduce noticeable delays, though...

I'm pretty sure that incoming calls to that line if made from outside the VOIP provider's service would transit some switch in Belfast.

Every VOIP line I've used has had noticeable latency, in my experience, and calls coming in from that line do have a little more.  However, I haven't received any calls from North America on that line -- it's mostly an interesting set of wrong numbers, and a decreasing number of calls from coworkers in the UK and Ireland (at work, most voice calls have shifted to Teams).  And while the latency is noticeable....it's not so bad as to really interfere with communication.   You just get used to it.

Wouldn't there be a similar phenomenon with cell phones traveling abroad?

[MikeTheActuary]

Are there any places that still use seven digit dialing?

7-digit dialing survived in area code 901 (Memphis), although I think 10 digit is "allowed" for local calls.

I understand that when 7 digit dialing will survive in much of area code 867 (Yukon/Nunavut/Northwestern Territories) when Canada adopts 988 next year -- areas local to Yellowknife, which has the 867-988 exchange will have to go to 10 digits, but 7 digit dialing will be preserved elsewhere.

[Poiponen13]

New format:
AAA-LL LL LL LL


No distinction between central office code and line number.