Here's the info regarding the above info (taken from one of the software
release PDF documents a few months ago:
Some V.32bis modems have difficulty making initial connection to K56Flex
modems, due to V.8bis tone.
Introduced in: All versions of K56Flex code after 1.0
To support the ITU standard V.8bis (Voice Call Ready), a K56Flex modem
sends a tone at the beginning of modem training. This is commonly referred
to as CRe and is a dual tone (1375Hz + 2002 Hz) followed by a single tone
at 400Hz with a combined duration of approximately 500 ms. Although V.8bis
is designed not to interfere with V.32bis (supporting a maximum rate of
14.4 Kbps) modem negotiation, some modems do not successfully complete
modem training after reception of the V.8bis tone.
If your modem experiences problems connecting to a K56Flex modem, append
four commas (,,,,) to the AT dial string.
By default, each comma adds a two second pause to the modemís processing.
By adding four commas, your modem will dial the specified number, wait
eight seconds, then continue operation.
The S8 register on your modem contains the pause duration for the comma
option. You should not need to change it from its default value of two