Some Facts on Supervision

by The Kid & Co.

Answer supervision is the telco term for the signal sent back to indicate the call has been answered and billing should commence.

Many alternate long-distance carriers do not have this feature, so they start billing after a caller has been on a line for an arbitrary amount of time (usually 20-30 seconds).  This grace period can be spent listening to a ring, busy signal or even talking.

Obviously, this method of billing can result in billing errors of great magnitude.  Imagine what would happen if one chose to listen to a ring or busy signal for 3 hours.  This problem was covered in detail in an article appearing in the November 1985 issue of 2600 on page 2~74.

There is a fair share of telephone numbers out there that are free to call i.e., they do not supervise.  These should not be confused with 800 numbers, which do supervise, but carry no charge.  Telephone company recordings and various "secret" numbers often don't supervise.  Phones that are illegally hooked up to "Black Boxes" will defeat call supervision.  The latter is impossible in an Electronic Switching System (ESS).

To determine if answer supervision signals are sent back by a particular number, one only needs a telephone connected to an ESS made by AT&T Western Electric.  This phone must also he able to access the Call Forwarding feature.

First, attempt to forward your calls to the number to be tested.  Make sure to use a carrier which returns supervision if you are calling long-distance.  If you don't use AT&T or a carrier which uses answer supervision.  The results of the test will he inconclusive for the reasons discussed above and in the other article.

The forwarding process will connect you to the number being tested for supervision.  After the call has been "answered," hand up and dial your own phone number.  If you get a busy signal then the Call Forwarding has been rejected because the number is unsupervised.  Calls to that number are free when using a carrier which does return supervision.  If you get connected to the number, then it is supervised.  You have been billed for both calls and should make sure to unforward your calls.

This test is useful when compiling lists of test number that will be used throughout the country.  It would he a real plus to see supervisory information on the lists already in circulation.  During the research for this article, we noted that Equal Access really is equal.  I was surprised to find that both Call Forwarding and Speed Calling allow an optional 5-digit carrier access code to be specified.  Therefore it is possible to determine whether or not a long-distance carrier returns true answer supervision.

To test a carrier and obtain conclusive results, one should use the supervision test on the carrier using a known unsupervised phone number (a number that tested unsuped using the above test with AT&T as the LD carrier) and a known supervised one (any home phone will do).  If the test using an alternate carrier does not return the same results as AT&T, then the carrier does not return proper supervisor information.