Operation Manual

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FAX-L1000 Chapter 3: Technical Reference
3. NEW FUNCTION
3.1 High-speed Transmission
The image transmission time is reduced drastically compared with the previous models by the
V.34 modem (maximum transmission speed 33600 bps) recommended by ITU-T.
3.1.1 V.8/V.34 protocol
a) Outline
• 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 contains a modem circuit based on the previous
recommendation to connect with the previous modems and has upper compatibility.
• The actual data transmission speed is improved entirely on average by speeding the
modulation method and utilizing new techniques, such as the pre-emphasis technique
*1
for
increasing the S/N (signal-to-noise) ratio and the probing technique
*2
for measuring line
characteristics 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
*3
are available:
33600, 31200, 28800, 26400, 24000, 21600, 19200, 16800, 14400, 12000, 9600, 7200,
4800, and 2400 bps
• The modulation speed (baud rate)
*4
can be selected from among 2400, 3000, and 3200
symbols/sec (required) or 2743, 2800, and 3429 symbols/sec (option). The data
transmission speed can be set more finely than the previous modems.
NOTE
*1 The output level of a high-frequency zone with comparatively high noise
is raised, and then the transmission signal is sent.
*2 A tone signal known as a probing signal (L1 and L2) is output, and the
receiving side measures the characteristics of the line.
*3 The data signaling rate is recorded in the ITU-T standards manual. Image
transmission speed means the same as data signaling rate.
*4 The symbol rate is recorded in the ITU-T standards manual. Symbol rate
means the same as moderation speed and baud rate.
2743 symbol/sec cannot be used with this fax.