🚀 go-pugleaf

In article <1993Jan25.203845.8439@mav.com>, toddi@mav.com (Todd Inch)
wrote:
> 
> In article <betel.727244356@camelot> betel@camelot.bradley.edu (Robert Crawford) writes:
> 
> >	A more interesting (to me) question: How could someone _with_
> >caller ID screen calls that do not include the information? My idea is
> >for the "black box" to sit between an answering machine and the
> >telephone, and to not pass the ring signal unless the caller ID
> >information comes along...
> 
> Great - if you don't want to receive any long-distance calls.  Calls
> from other exchanges, especially in distant places, may not contain the
> CID info because the necessary SS-7 protocal has not be implemented
> everywhere yet.
> 
> Now if you can distinguish between "blocked" and "not available", that
> would work fine.  This is probably dependant upon your hardware, but
> may also be dependant upon how your local telco has things set up -
> they may send one message for both conditions (although hopefully not!)

There is a parameter that can be included in the CLID message that
identifies the reason for absence of the DDN.  The paremeter can be set to
one of two values, indicating either that a) the information has been
suppressed (blocked) or b) the number is not available.

The problem is knowing whether or not the phone company will choose to
include this information parameter when the DDN is unavailable.  I do not
know whether or not they will, I don't think that there is any requirement
to do so.

It should be easy enough run a little test to find out, assuming that your
CLID phone displays messages such as "Private" and "Out of Area" when
appropriate.  These messages are based on receipt of this parameter.

dam

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Dana Merrill                                Bell Northern Research
DMerrill@BNR.CA                         Research Triangle Park, NC
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