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5.6
V.34 MODEM Technology
The image transmission time is reduced drastically compared with the pre-
vious models by the V.34 modem (maximum transmission speed 33600
bps) recommended by ITU-T.
5.6.1 V.8/V.34 protocol
(1) Outline
*1 The output level of a high-frequency zone with comparatively high
*2 A tone signal known as a probing signal (L1 and L2) is output, and the
*3 The data signaling rate is recorded in the ITU-T standards manual.
*4 The symbol rate is recorded in the ITU-T standards manual. Symbol
• The V.8 protocol is used as the startup protocol to move to V.34. The
V.8 protocol enables connection with fax machines, data modem and
equipment using existing V-series modems. The V.34 modem con-
tains a modem circuit based on the previous recommendation to con-
nect with the previous modems and has upper compatibility.
• The actual data transmission speed is improved entirely on average by
speeding the modulation scheme and utilizing new techniques, such as
the pre-emphasis technique
ratio and the probing technique
and optimizing the modem operation according to the line condition.
• The V.8 protocol, V.34 pre-protocol and post-protocol use full-duplex
transmission to speed the processing.
• Fourteen image transmission speeds
33600, 31200, 28800, 26400, 24000, 21600, 19200, 16800, 14400,
12000, 9600, 7200, 4800, and 2400 bps
• The modulation speed (baud rate)
3000, and 3200 symbols/sec (required) or 2743, 2800, and 3429 sym-
bols/sec (option). The data transmission speed can be set more finely
than the previous modems.
noise is raised, and then the transmission signal is sent.
receiving side measures the characteristics of the line.
Image transmission speed means the same as data signaling rate.
rate means the same as moderation speed and baud rate.
2743 symbol/sec cannot be used with this fax.
G3 FACSIMILE COMMUNICATIONS
*1
for increasing the S/N (signal-to-noise)
*2
for measuring line characteristics
*3
are available:
*4
can be selected from among 2400,
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