Identifying Your Telecom Neighborhood

Your telecom neighborhood is defined by the LATA, or Local Access Transport Area, from which you’re calling. Although LATAs are regional designations, they were initially drawn up based on total population for the geographic area. This is the reason that states like Texas and California with higher population densities have 10 or 15 LATAs apiece, and the entire state of Wyoming makes up a single LATA.

Understanding the role of local carriers and long-distance carriers in LATAs

No phone call can legally cross a LATA border unless a long-distance carrier is handling it. Your local carrier, be it Ameritech, Bell South, or some other company, must transfer the call to a long-distance company like MCI, Sprint, or AT&T in order to complete the call. Figure 3-1 gives you a general idea of how the LATAs are set up in your state.

Figure 3-1: The network of LATA boundaries and LATA numbers for the U.S. is pretty complex.

 Remember  LATAs are not area codes and don’t make up any part of a telephone number. The geographic area of LATAs is much larger than the area covered by area codes. In many instances, area codes exist in more than one LATA.

LATA numbering and borders

Every LATA has a specific three-digit number to make it identifiable. Say you’re talking about calls that are failing in Oklahoma, for example. You could ask whether the problem appears to be happening more in LATA 536 than in LATA 538 or whether the issue is restricted to just LATA 538. LATA numbers are generally lower in the Northeast, and the numbering increases as you move west across the U.S. toward California. As populations explode in North America, new LATAs are constructed. You can easily find newer LATAs because they are all numbered in the 900s, like LATA 961 in Texas.

LATAs generally end at the state border, but there are many LATAs that cover more than one state. For example, half of LATA 956 is in Virginia and the other half is in Tennessee. The LATAs are not usually spit 50-50, but it is not that uncommon for a LATA to bleed over into a small section of a neighboring state.