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From: kam@dlogics.COM (Kevin Mitchell)
Newsgroups: comp.dcom.telecom
Subject: Re: Questions About the GTE Airfone
Message-ID: <15323@accuvax.nwu.edu>
Date: 7 Dec 90 16:30:48 GMT
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X-Telecom-Digest: Volume 10, Issue 873, Message 8 of 9


In article <15223@accuvax.nwu.edu>, seanp%undrground@amix.commodore.
com (Sean) writes:

> When you insert your credit card, the information (number, exp.
> date, etc. ) is sent via 300 baud signal to a ground station. (REAL
> TIME). The ground station then confirms or denys usage, and proceeds
> from there.  Actually, the handset is not released until then card is
> approved.

Is the data encrypted? It sounds like a massive security leak,
broadcasting sensitive information about a card like that. I know all
the arguments about privacy, not listening to certain frequencies,
etc., but a credit card pirate with an all-band receiver isn't going
to be "nice" about it.

>      894 - 896 MHz (5 KHz spacing). Assignment is done in the same
>      manner as cellular. It picks an available frequency from what the
>      ground station tells it. AM mode is used for modulation.

This is different from what I've heard. Popular Electronics has a
scanner column, and reported several 470 MHz band frequencies where
you can pick up air phone calls. I've found some there.


Kevin A. Mitchell       (312) 266-4485
Datalogics, Inc         Internet: kam@dlogics.UUCP
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Chicago, IL  60610      FAX: (312) 266-4473