Silly technical question from a non-technical person

[Josh M. Osborne]

In message <9508172055.AA15978 at spirit.aud.alcatel.com>, Daniel R. Oelke writes:
[...]
>I know someone who *used* to be in the ATM transaction 
>business, but is no longer.  Is the code from a credit card
>reader DES encrypted?  We could be possible "tap" the serial
>port between the reader and the modem and get a byte 
>stream in that manner.... but then again, my knowledge
>of those beasts is pretty limited.

At least some of the cc-reader protocalls are not encrypted (but
they are rather cryptic on their own :-).  I don't know how common
this is 'tho.