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FAX ASSOCIATED OPTIONS
A number of options can be changed without any effect on fax opera-
tion. These include items like speaker volume and pause for carrier.
Appendix E lists the AT commands and indicates how they may affect
fax operation. These commands can be incorporated by personal prefer-
ence into the initialization command. The user should compare fax
operation requirements with Appendix A and if necessary generate an
initialization command string compatible with the software and the
modem.
Stored FAX Profile
Another alternative is to develop a fax initialization command and store
it in one of the user defined profiles. Fax initialization would include
the command that recalls that profile for fax operation. The user must
keep track of option changes between fax transmissions and if required
reset the fax profile for the next fax transmission.
CLASS 1 DETAILS
Operation as a fax modem complies with EIA-578; details of Class 1
operation and compatibility are found in that standard. There is no need
to be familiar with these details since they are handled by the Class 1
software package, but this section briefly summarizes some of them.
As a Service Class 1 facsimile DCE, the V.3400 provides the basic
services required to support Group 3 facsimile operation. Support from
a Class 1 facsimile DTE is required to implement the CCITT T.30
recommendations for fax document transmission and the CCITT T.4
recommendations for encoding fax images. Using software control the
modem can
• connect calls
• generate messages
• detect waiting and silence
• transmit and receive data
• provide HDLC data framing, transparency, and error detection
The modem also filters data streams to and from the DTE in accordance
with the Class 1 specification.
V.3400
Fax Operation
9-3
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