LDPC-Merritel will do everything possible to avoid delays. Just pick up any extension of the line you want to test and dial the toll-free number. You will hear a recording which will identify the current long-distance carrier for that line. This test number can be used nationwide. All carriers use various factors for determining these rates including, but not limited to, volume and average length of call.
Interstate rates refer to calls from one state to another state.
Some states have a single LATA while others have several. Yes, but the default carrier for your LATA usage is your local telephone company. You should contact them and compare the rates for the areas you call the most. As of February 1999, you have the right to choose a LATA carrier over the local phone company, but you have to request it. The savings in the long run with LDPC-Merritel carriers will offset this charge.