danny@uunet.uu.net (Danny Wilson) (02/01/90)
>From: well!slf@lll-crg.llnl.gov (Sharon Lynne Fisher) >Can anybody point me to people who can talk to me about fax Group IV >specs and how they differ from Group III? >Also, I'd be interested in pointers to any other "new and nifty >things" under development for fax technology. Since IDACOM is now developing a comprehensive test bed for doing Conformance Testing for all layers of the GIV Fax protocol, there are several people in our organization that know about this. Also, Ricoh, Canon, and Panasonic are all using our equipment for the development of their new GIV fax machines (I've seen them), so I hope that we can help you out. Danny Wilson danny@idacom.uucp IDACOM Electronics alberta!idacom!danny Edmonton, Alberta X.400 danny@idacom.cs.ubc.cdn C A N A D A Voice +1 403 462 4545
hrs1@cbnewsi.ATT.COM (herman.r.silbiger) (02/11/90)
Regrading the request for information on Group 4 fax standards, I will
list them below:
There are actually three types of G4 machines defined, Classes I, II,
and III.
Class I transmits on a line by line basis, has a standard resolution
of 200x200 pels/inch (optional: 240x240, 300x300, 400x400).
Class III transmits on a page basis, has a standard resolution of
300x300, the others optional, and has mixed-mode as a standard, i.e..
it can transmit and receive pages with character coded and raster
graphics coded information intermixed on the same page.
Class II is like class III, but can only receive mixed-mode, not send
it.
Class I machines cannot directly interwork with class II and III
machines, since they use different protocol stacks.
G4 machines also cannot directly interwork with G3 machines, although
many current machines have G3 capability included as a separate board.
G4 Recommendations:
T.412 Document Structures
T.415 Open Document Interchange Format
T.417 Raster Graphics Content Architectures
T.431 Document Transfer and Manipulation - Service Definition
T.432 Document Transfer and Manipulation - Protocol Specification
T.501 Document Application Profile for the Interchange of Formatted Mixed
Mode Documents (for Class II and III)
T.503 Document Application Profile for the Interchange of Group 4 Facsimile
Documents (for Class I)
T.521 Communication Application Profile BT0 for Document Bulk Transfer Using
the Session Service Defined in Rec. T.62bis (for Class I)
T.522 Communication Application Profile BT1 for Document Bulk Transfer (for
Class II and III, uses session service defined in X.225)
T.561 Terminal Characteristics for Mixed Mode of Operation MM (for Cl II &
III)
T.563 Terminal Characteristics for Group 4 Facsimile Apparatus
Image coding for G4 follows Rec. T.6.
Work is currently under study in CCITT for enhancing Group 3 to add
higher resolutions (to 400x400), T.6 encoding, and an ISDN interface,
while maintaing full compatibility with existing G3 equipment.
Currently, only G4 is available with a 64 Kb/s interface.
Equipment conforming to ODA profiles level 2 and 3 also have the
capability of sending raster graphics image pages.
Herman Silbiger