Let’s suppose you have made a plan to migrate your office telephone system from analog phone lines to VOIP trunks.  Maybe you are doing this to reduce your monthly telephone bill to 85¢ as I blogged recently.  But regardless of why you are migrating, clearly you will want to carry out the migration in a way that minimizes the risk of disruption of incoming or outgoing telephone service.  In this article I describe a migration path that worked well for our firm, and along the way I explain a little bit more about SIP trunking and how it works. Continue reading →

In a previous blog post I discussed two companies that you probably never heard of that make telephone calls possible — Neustar and iconectiv.  These companies administer the NPAC database, which is a database that gets consulted each and every time that any one dials a telephone call to a US (non-toll-free) telephone number.  A million times per day, a telephone call gets placed to a US telephone number, and a million times a day, a lookup happens to this NPAC database, without which the phone call would not be able to reach its destination.  And if you are like me, you never heard of either company.

In this blog post I will discuss another group of companies that you probably also never heard of, that are responsible for a super important part of the way that telephone calls take place.  This category of companies does not, so far as I know, have a name.  I will call them “VOIP wholesalers”.  Some of these companies are called Onvoy, Bandwidth, Paetec, Peerless, Level 3 Communications, XO Communications, and Aerialink.  I had heard of Level 3 before, but I only knew them as an Internet company.  The other three companies I had never heard of at all until very recently.  What do VOIP wholesalers do, and why should you care? Continue reading →

Whenever you dial a telephone number that is located in the US, somehow your telephone company needs to be able to figure out which telephone company will complete the call.  So for example suppose your cellular carrier is AT&T and you pick up your cell phone and dial a phone number.  One of the first things that AT&T must do is somehow to figure out which telephone company is responsible for that phone number.  Maybe that phone number is handled by Verizon.  If so, then somehow AT&T needs to know to send your call to Verizon which will complete the telephone call.

How does your telephone company come to learn which telephone company is responsible for that phone number?  Keep in mind that the person you are calling might “port” their cell phone number tomorrow from Verizon to T-Mobile.  If so, then if you were to dial the same telephone number the day after tomorrow, your telephone company would need to know to send your call to T-Mobile instead of sending it to Verizon.

How does this work?  And how does this relate to “number portability”?   Continue reading →