How does a hackers exactly get their modem to handshake to the modem
they are tareting when dial up hacking?

I suspect that dial-in hacking and war dialing is an almost forgotten
art for the 'hackers' of today. And what's more, with modern modems
being multi-standard and able to step down, it should be no challenge
at all.

When a modem is set to answer incoming calls it will start the
handshake with a type of introduciton about the highest speed it can
speak, the calling modem will then try to establish a communication
with that protocol or, if that one is not supported, will suggest an
alternative. This the squealing and hissing you hear when listening to
a modem connecting.

Things were a little more difficult in older times, where the were a
few mutually exclusive protocols, you needed to know what you were
dialing into. I have an old acoustic-coupled modem that is switchable
between 1200/75 and 300 baud. However, even then there were a limited
number of options and the process of elimination was not complex.

A good overall look at modems:
http://www.hardwarecentral.com/hardwarecentral/tutorials/56/1/

See specifically the second page which outlines the most common
standards:
http://www.hardwarecentral.com/hardwarecentral/tutorials/56/2/

A similar outline:
http://www.webopedia.com/quick_ref/dialup_modem_standards.asp

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Clarification of Answer by sycophant-ga on 24 Jan 2003 02:20 PST

It seems I accidentially submitted this before I had really concluded my reply...

I hope this information clarifies things for you.

Regards,
sycophant-ga

Since the modem protocol is standardized, such a cracker would
probably dial in, the remote modem would report its baud rate, and his
program would conform to that baud rate.

Detecting Bits, parity settings, and hardware flow control would be a
little tougher, but bits is pretty standard at 7 or 8, hardware flow
control is on or off, and parity could also be determined by software
post-processing.

A nice little perl utility is available here:
http://mysite.mweb.co.za/residents/rdawes/