Table of Contents
Advertisement
12. Fax Protocols
12. Fax Protocols
12.1 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:
Partial page
(High-speed Modem
Signal)
300 dps Modem Signal
Re-transmission for
error (High-speed
modem Signal)
300 dps Modem Signal
158
Transmission
Field Service Ver. 1.0 Apr. 2005
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 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)
4507M501AA
Advertisement
Table of Contents
