local telephone numbers

Many apartment buildings have some sort of buzzer system for the front door so that residents can conveniently allow their guests to enter without have to (gasp!) physically walk somewhere to (gasp!) manually open the door. (for the record, I heartily approve of this feature)

There are several variations of buzzer systems ranging from the archaic hard-wired type that is connected to a dedicated intercom unit in the apartment to more modern types with a telephone “directory” of sorts and end up calling a phone number.

My building has the latter, and after having lived here for a few months I decided it was finally time to hook my phone up to the system. There was one little catch: the buzzer system actually makes real phone calls and it only has a local calling plan, meaning anyone with a long distance number is out of luck.

This is the part where we cheer for Google Voice, which is the best thing for phones since Caller ID.

Using Google Voice, you can essentially buy a phone number anywhere in the country and route it wherever you want including your existing mobile phone. So all I had to do was to buy a number that the buzzer system considered to be local and I’d be laughing.

Except… what, exactly, is a local telephone number these days? In olden times, area codes were pretty reliable indicators. But then people started getting business lines and fax lines and cell phones and pretty soon the phone companies started running out of numbers and we got split plans and overlay plans and the much hated and feared ten digit dialing but lucky for us the world didn’t end. [nb, my childhood incorporated a split plan, having grown up in 201 for my entire childhood, we were abruptly shoved into the far inferior 973 which was mildly traumatizing at the time, but I’ve since worked out all those issues with my therapist]

So anyway, once we were dialing 10 digits for all calls, consumers no longer had a clear signal as to what was a local call and what was not… except we all got cell phones a few years later and pretty much stopped caring about that archaic concept known as “long distance”.

Save for pesky little things like door buzzers with el cheapo local dialing only. My building manager gave me some dramatic warnings about how not all Google Voice numbers were considered local to our door buzzer and sent me off on somewhat of a wild goose chase that ended up with me on one of the most deliciously geeky websites on the entire intarwebs: local calling guide.

It’s kinda hard to know what to do with this page when you first see it, but after some digging around, it turns out to just be awesome. Start by pondering list of NPA codes. Normal human beings will refer to these things as “area codes” but hey, now that we’ve learned the precise terminology, we should adopt it, right? Let them eat “numbering plan areas”!

From there, you will need to find the NPA-NXX-X of both the buzzer system and the potential Google Voice number you might want to acquire. I haven’t actually been able to figure out what NXX-X stands for (if anything), but the practical piece of information is:


So 201 is your NPA, then 555-1 is your NXX-X. Once you have identifed the NXX-X of both the buzzer system’s phone number and whatever number you might get from Google Voice, you simply check the LATA (local access transport area) column. If the two NXX-X numbers are in the same LATA, then you can dance a jig because it means the buzzer will consider a call to your GV number to be local.

A few extra tips though regarding the GV numbers. You can see that are registered and owned by bandwidth.com. Note the column labelled “eff. date”, which is when the number went into service. If the date is very new, then it could be possible that the back end system your door buzzer hooks into might potentially not know about the new NXX-X and consider it to be in a different LATA, and hence refuse to make calls. I chose an NXX-X that was registered in 2009 just to be safe.

[bonus fun fact: most of northern Colorado shares the 970 area code, but not all of the NPA-NXX-X are in the same LATA. This explains why calling from Ft. Collins to Grand Junction is indeed local but calling South Baggs is not]

And once you get the buzzer hooked up to GV, well… all sorts of interesting things can happen, since GV numbers happen to be quite programmable. The fun stuff you can do with them is left as an exercise to the reader.

Be sure to check out the SAQ or seldom-asked questions. I totally ♥ the extreme nerd factor on this site.