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From: mitel!Software!grayt@uunet.uu.net (Tom Gray)
Newsgroups: comp.dcom.telecom
Subject: Re: Payphones and DTMF Dialling
Message-ID: <15606@accuvax.nwu.edu>
Date: 21 Dec 90 13:47:34 GMT
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X-Telecom-Digest: Volume 10, Issue 898, Message 5 of 11


In article <15531@accuvax.nwu.edu> U5434122@ucsvc.ucs.unimelb.edu.au
writes:

>As I described earlier, Telecom Australia has begun installing debit
>card telephones, which have fancy LCD displays and pushbutton keypads,
>instead of rotary dials (my, we are backward, aren't we.)

>I have been trying to discover why these payphones do not have DTMF
>dialling enabled.  I accosted an installer yesterday and grilled him

>[Moderator's Note: Disabling the mouth until supervision would prevent
>the phone from being used to call directory enquiries or the operator;
>both of whom answer unsupervised, no?  PAT]

Disabling the mouth piece would prevent the customer from placing an
operator assisted call or conversing with an intercept operator.  In
any event supervision is provided to the originating office by the
CAMA office. The CAMA office does this to instruct the originating
office to perform the ANI spill. Only then will the customer be
connected to the operator. Thus a local office has no way of knowing
that the call has been completed.
 
Operators may converse with a payphone before or after supervision is
given. Operators may have to request extra payment on an existing call
etc.

Fraud is prevented by disablng the DTMF pad when the customer is
connected to an operator. This is done by either reversing the
battery to the set or by providing +48v supervision.