CPC091692

                The Complete Communicator for DOS
    Why Can't CCOM Automatically Detect FAX, Voice, and Data
                When Those $100 Switch Boxes Can?


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To the matter of "automatic detection of voice, fax, and data,"
The Complete Communicator actually works very similarly to many
of the switch boxes on the market.  Unfortunately, communications
standards do not provide adequate reliable information for
detection of what type  of call is coming in.  Both voice callers
and incoming modem transmissions require that the answering
device initiate contact.  Your voice callers expect to hear
"Hello" or some equivalent before they start talking, and modems
require the answering modem to issue a modem tone (sort of a
screeching noise) before communications can begin.  The fax
communications protocol also requires that the answering device
initiate contact.  Some fax machines issue, what is called, CNG
tones (little beeps 3 seconds apart) while waiting for an answer.
Use of the CNG tone is optional in the Group III fax
communications standard, and is not universally implemented (some
fax machines do it and some don't) and as such, it is an
unreliable means of detecting FAX.

The switch boxes typically use CNG tone detection to distinguish
fax calls.  While this is useful, again, because it is
implemented in some fax machines, and not in other there is no
guarantee of fax detection.  For voice and modem detection, a
number of schemes are use.  Some devices play a brief modem tone
on the line to see if a modem answers.  The problem here is that
your callers get blasted with the modem screech.  Others ask your
caller to say a particular word so  that voice can be detected.
This can be confusing and makes many callers uncomfortable.
Others use a canned voice to ask callers to enter a touch tone
much like CCOM does (although with CCOM you can record your own
personalized greetings).   Almost all of these boxes also play a
simulated ring back (or worse, silence) while they are waiting
the 3 seconds to detect CNG tones.  We have yet to come across
one whose ring back sounds anything like that of the phone
company and the prolonged silence often results in callers
hanging up.  Callers will hear ringing, then a pause, a different
ring, and then finally, your answering machine or receptionist.

As you can see, auto call detection is an imperfect science at
best.  We have chosen the implementation found in CCOM because it
is the most reliable and allows our users to present the most
professional image to their business associates.  As always, we
stay abreast of communications technology and will implement a
more automatic system if a reliable alternative comes along.