internal PC plug-in card. External stand alone units can be
connected to any computer with a standard RS-232 serial port.
This computer need not be a PC.
EIA CLASS 2 FAX COMMAND
The EIA class 2 fax command is a set of AT fax commands defined
by EIA/TIA (Telecommunications Industry Association) for
controlling faxmodems from a computer through the serial RS-232
interface. Faxmodems and fax software supporting this standard
will work together. The problem is that there are several
revisions of this standard. Implementations conforming to
different revisions may not work together.
AUTODETECTION OF FAX OR DATA CALL
Fax and data modems have different handshaking signal sequences
at the beginning of a call as specified by the CCITT. It is
possible to automatically detect whether an incoming call is from
a modem or a fax device by testing and recognizing its initial
handshaking sequence. A modem with this capability can make a
computer process both data and fax calls on the same phone line.
An example is that a BBS (Bulletin Board System) can also receive
faxes. ZyXEL modems can automatically detect data and fax calls.
ZyXEL also includes a fax receiving and printing program to allow
a BBS to receive faxes and print them out in the background.
CALLER ID
Normally called Caller Number Delivery (CND), this is a service
available from phone companies in several parts of USA and some
other countries. With this service, the phone company sends
calling party information along with ring signal to the called
party. The major part of this information is the telephone number
of the calling party or caller ID. ZyXEL modems can detect and
report caller ID.
DISTINCTIVE RING
This is a service available from some phone companies in some
areas of the USA and in other countries. You can have several
phone numbers on the same subscriber phone line. The phone
company sends a different ring signal for each phone number
assigned to the same line. You can have your phone equipment
answer only a certain type of ring corresponding to a certain
phone number. ZyXEL modems can be set to answer on one or a
combination of four types of ring signals. The problem is that
every country may have a different specification for different
ring types.
DIGITIZED VOICE
Modems with digitized voice capability can digitize an incoming
voice message with the computer storing it as a file. The modem
