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Drivers for Fax Modems

Dear All,
 I am planning to get a driver for a fax mode but I have not decided which one is best, Class I or Class II?

Any recommendation will be greatly appreciated.

Thank you
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1 Solution
Lee W, MVPTechnology and Business Process AdvisorCommented:
Class II.  Its enhanced class I.  And should be compatible with Class I as well.  

From http://www.hylafax.org/Modems-PeterChen/05faxmodem.html
V.1.f. Class 1 & Class 2
In the past, no standard existed for a microcomputer to deal with a fax board. As a result, the software for a particular fax board won't work with another fax board from a different manufacturer. (Although CAS has been moderately successfully, it hasn't become the industry standard.) The Electronic Industries Association/Telecommunications Industry Association (EIA/TIA) has been developing new standards (Class 1 & Class 2) for microcomputers to communicate with fax modems. As a result, you can buy a software program that will work with Class 1 (or Class 2) fax modems from different manufacturers.

The Class 1 standard provides minimal hardware support for sending a fax from a microcomputer, while Class 2 adds over 40 AT-command set instructions and places more functionality into the modem.

Note that the Class 2 standard is not expected to be finalized until August, 1992. In fact, most "Class 2" fax modems in the market today are based an obsolete draft. (It has become epidemic for computer vendors to announce products that are supposed to meet a standard while the standard doesn't even exist yet.)
Lee W, MVPTechnology and Business Process AdvisorCommented:
More info:

Check out the specifications for a FAX modem, and you'll find reference to the modem's compliance with a certain "class" ... and an additional reference to the "group" the FAX modem belongs to. That's OK as long as you understand the differences between them:

# CLASS 1 MODEMS utilize a series of Hayes-type AT software commands to control FAX boards. Class 1 modems do not have the ability to automatically detect whether an incoming call is data or FAX. The modem will have to be set for one or the other.
Comment from John Navas (JNavas@NavasGrp.com): USRobotics modems support Adaptive Answer in Class 1 mode.

# CLASS 2 MODEMS have hardware that provide the ability to automatically detect whether the incoming call is a data call or a FAX call.
Quite simply Class 2 is a newer standard that lets the modem do the processing but it will depend on what modem you have and what class it suuports so you may not have a choice.  Class 2 has been around for quite some time now so you should be ok unless you have a really old modem.

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