Indiana | Illinois | Michigan

Overlay vs Split

The industry likes overlays. I don't.

Some time back in the 1990's the industry got the idea that splitting an area code was bad - to the point where it was the worst thing that they could do. The horror of changing an area code that had been in use for years was too much! So the industry started recommending, regardless of the size of the area code, that any new relief be an overlay.

Mistakes in Illinois
I don't blame the industry. I have seen splits used poorly ... one does not have to look any further than Chicago for an example of an inappropriate split. While I agree with the original 317-708 split and can accept the eventual 708-630-847 split of the suburbs, the 312-773 split was wrong. 312 was too small of an area to split.

Not only did the split of 312-773 cause millions of people in Chicago to change their area code while a small area in "the loop" kept 312, the split led to the premature introduction of the next area code. As of July 2013: 773 has no codes available, 312 has 85 codes available, and 872 has 61 codes assigned. Theoretically if 312-773 was an overlay there would be no 872 codes in use as the remaining 312 codes could be used in the exhausted 773 area.

The outrage over splitting small areas such as 312 has affected decisions in larger area codes where splits make sense. Illinois has moved forward from the 312-773 split by (appropriately) putting in place overlays for the rest of the Chicago suburbs and overlaying 312-773 with 872. But part of that "move forward" was a move to use overlays EVERYWHERE in Illinois - including in the large area codes down state.

Large Area Overlays
The first of the large area code overlays in Illinois took effect in 2007 when the 815 area code in northern Illinois was overlaid with 779. Effective February 17, 2007, all customers in 815 are forced to dial eleven digits to make a local call. (In addition to the overlay decision, the Illinois regulators require 1+ dialing in overlays instead of allowing 10 digit dialing.)

We can look at area code 815/779 over six years later and see the effect. While 815 has exhausted (no codes available) there have been only 61 codes assigned in 779. These codes are assigned in 29 rate centers. In 21 of those rate centers there is only one 779 area code exchange. (Rockford has 16, Joliet has 9, the other six have three or less 779 area code exchanges.)

Thanks to the overlay EVERYONE in area code 815 is dialing 11 digits for every call ... even though in most rate centers there are no or only one 779 area code exchange to dial. Does that make sense? Is giving up the convenience of seven digit dialing so people outside of your area code do not need to learn your new area code a good trade off?

The argument for using an overlay is that people do not have to change their phone number. But the reality for residents of 815 is everyone's phone number has changed. Nearly everyone's local number is now 1815xxxxxxx - with either no one in most areas or just a few subscribers in 29 rate centers with 1779xxxxxxx local numbers.

I do not consider that a good thing.

The Future
For Illinois the decision is made. When 217 exhausts Illinois will inflict an overlay on central Illinois. When 618 exhausts Illinois will inflict an overlay on southern Illinois. And for years after the overlay goes into effect most residents will see little or no benefit to their 11 digit dialing. For most "relief" just means more digits to dial across town.

The IURC did not learn from the mistakes in Illinois. In the past Indiana has done well splitting the large 317 area code into 317-765 in 1997 and the large 219 area code into 219-260-574 in 2002. But when decision time came to relieve the large 812 area code the IURC fell in line with the industry and went with an overlay. When we look back at 812 six years after relief I wonder how many rate centers will have 930xxxxxxx numbers. Will it be worth dialing 10 digits, or 812 in front of nearly every local number, to avoid changing the area code?

When it comes time to relieve 317 Indiana can learn from the mistake of splitting 312-773 and appropriately use an overlay. I don't see that as a problem - if the IURC can approve a large area overlay for 812 they will certainly approve a small area overlay for 317.

How is Michigan Doing?
All the talk above seems to be "Illinois bad / Indiana good" ... so how is Michigan doing? Not bad. The 313-810 split in 1993 being followed by the 810-224 split in 1997 was not the best timetable ... and 810-586 was only eight years after 1993. But for the most part Michigan has kept with the large area split/small area overlay opinion that I support. Michigan did use a "county line split" for 248 and 586 which leaves an interesting shape for 810 wrapped around Oakland and Macomb counties. But overall Michigan has done well. (PS: I don't hate Illinois but they could do better.)

Comments on the Industry View
I understand why the industry likes overlays. They do not look at numbering from a user's viewpoint. End users look at numbering from two directions: "what is my number" and "what do I have to dial to make a call". The industry is addressing the "what is my number" question but they have the plan that eventually all calls will be dialed 10 or 11 digits anyway so they ignore the "what do I have to dial" question.

In the 1990s "eventually" was not that far off. The industry predictions placed the need for "longer than 10 digit numbers" as early as 2010. Area codes were exhausting often and the industry was trying to avoid multiple number changes. But nearly 20 years later "eventually" is now predicted to be more than 40 more years away.

I do not ignore the "what do I have to dial to make a call" question. Dialing is a key part of any numbering plan. And serving the end users and their needs is more important than serving the needs of the system.

Unfortunately the curse of the overlay is here to stay ... one of the arguments used in favor of an overlay for 812 was that only one other area code was split since the Indiana and Michigan splits of 2002. Without an investigation into why those areas were overlaid and whether or not each was a good decision Indiana has caught the overlay bug. A virus for which there is no cure but prevention.

At least my code and dialing pattern will last until 2044 ... thanks to a split.
Written / Compiled for
Telecom Indiana