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5. Fax Protocols (PagePro 1390 MF only)

5-1. G3 ECM (G3 Error Correction Mode)

G3 ECM is the error correction system newly recommended by Consultative Committee
of International Telephone & Telegraph of 1988.
By G3 ECM, documents are divided into blocks (called partial page) for transmission. If
any error takes place in any frame (one partial page consists of 256 frames) on a partial
page, the receiving party generates the retransmit request with erroneous frame num-
bers.
Here is an example where frame 1 and frame 3 are subjected to error:
4558F3E602DA
Transmission Receiving
Error
Note: If one page end and
consists of plural number of
partial pages, PPS.
NULL signal is transmitted
from the transmission side.
Partial page
(High-speed Modem Signal)
300 bps Modem Signal
Re-transmission for error
(High-speed modem Signal)
300 bps Modem Signal
Partial page end and End
procedure
Re-transmit request
(MCF is repeated if there
is no error)
Re-transmission
Partial page end
Message check
(Received without error)