If you have never used a CallBack feature on a bulletin board system
you probably don't know what this thing is designed to do.
Basically, it check to see if a new user is actually located at the
phone number he says he is. If he is, you, the Sysop, have a definitive
method to trace a user back to a real location. As we all know,
verification of a user is a difficult and time consuming operation.
Once the system verifies the new users phone number, it upgrades his
system acccess to that of a 'regular' user. The level of upgrade is
set by you. It also allows you to see if a user is attempting to open
up a multiple account on your system.
This, essentially, is the basic function of a CallBack door or utility.
IMPORTANT: Please note - if setting this door up for standard N.American
phone formats, it will NOT call long distance outside of the xxx-xxx-xxxx
telephone format. Therefore, it can not be used to validate European
callers when it is set up for N.American dialing. 
(This may come later in its developement).

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                  553     935  59.1% -lh1- 1785 Dec  5  1993 autovalidate.cfg
[generic]                   58      73  79.5% -lh1- f440 Dec  5  1993 BadNumbers.txt
[generic]                   87     100  87.0% -lh1- 96a6 Dec  5  1993 BadNumberUse.txt
[generic]                  160     212  75.5% -lh1- f848 Dec  5  1993 BadNumberWarning.txt
[generic]                  228     355  64.2% -lh1- ed8e Dec  5  1993 CallBackMsg.HangUp
[generic]                  195     278  70.1% -lh1- 8d54 Dec  5  1993 CallBackMsg.StayOn
[generic]                  647    1125  57.5% -lh1- 6764 Dec  5  1993 Continue
[generic]                  136     167  81.4% -lh1- b6e5 Dec  5  1993 Duplicate
[generic]                  583    2270  25.7% -lh1- 7e43 Dec  5  1993 DupNums.txt
[generic]                    4       4 100.0% -lh0- 209b Dec  5  1993 LocalAreaCode.txt
[generic]                   81     160  50.6% -lh1- 8764 Dec  5  1993 LocalExc.txt
[generic]                  128     153  83.7% -lh1- 7dde Dec  5  1993 Manual
[generic]                  436     675  64.6% -lh1- 9a55 Dec  5  1993 MessageBody
[generic]                  205     270  75.9% -lh1- a08d Dec  5  1993 MessageBodyNoAttach
[generic]                  138     161  85.7% -lh1- afee Dec  5  1993 NoLDCall.txt
[generic]                   94     104  90.4% -lh1- b4ab Dec  5  1993 Notice
[generic]                  112     138  81.2% -lh1- e989 Dec  5  1993 Notify
[generic]                 4468    7252  61.6% -lh1- 9a9a Dec  5  1993 PhoneConv
[generic]                   71      73  97.3% -lh1- 2365 Dec  5  1993 SingleNameNotify.txt
[generic]                  213     272  78.3% -lh1- fa3c Dec  5  1993 SingleNameWarn.txt
[generic]                  328     542  60.5% -lh1- adcc Dec  5  1993 start
[generic]                    9      96   9.4% -lh1- d943 Dec  5  1993 time.dat
[generic]                  314     479  65.6% -lh1- 3cc5 Dec  5  1993 Warning
[generic]                  177     229  77.3% -lh1- 560e Dec  7  1993 readme.first
[generic]                13512   27652  48.9% -lh1- 049a Dec 23  1993 autoval
[generic]                10541   28720  36.7% -lh1- 3691 Dec 23  1993 autoval.docs
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        26 files   33478   72495  46.2%            Jun 16  1995