Table of Contents
Advertisement
2. COMMUNICATION CONTROL
2.1.2
Modem fallback sequence
• Fallback sequences of TCF and CTC are shown as follows:
A. V17, V29, and V27 ter
Ability of a remote station
V27 ter/V29
V27 ter/V29/V33 V17
• On the transmission side : If PPR is received four times, a modem is set in the fallback
• On the reception side
B. V34
• Line quality is always water by modem.
Optimum speed is automatically selected on-the-fly.
2.1.3
V8/V34 sequence
A. V34
(1) Outline
• The 33.6kbps data transmission method and protocol including the V8 protocol. As for
each of full-duplex and half-duplex, startup handshake until data transmission starts is
divided into four phases, phase1 to 4, and signals used in each phase are regulated.
(2) Features
• Full-duplex (echo canceler method) / Half-duplex method are regulated (for data / FAX
respectively)
• 2400, 3000 and 3200 symbols / sec (mandatory) and 2743, 2800 and 3429 symbols /
sec (option) QAM synchronous transmission at each symbol rate
• Communication at each signal rate of 33600, 31200, 28800, 26400, 24000, 21600,
19200, 16800, 14400, 12000, 9600, 7200, 4800 and 2400 bps
• Four-dimensional-symbol trellis coding
• A 200bps sub channel which can be used as an asynchronous second channel (option)
• Negotiation in which characteristics of a line is measured before transmission starts and
the maximum communication speed is achieved by finely adjusting the transmission
parameter, based on the result of measurement (carrier / frequency / equalizer / symbol
rate / level, etc.)
• Data transmission in the super frame with the hierarchical structure
32
96/V.29
72/V.29
144/V.17
120/V.17
V27 ter
state.
: In case of sending PPR, when the number of error frames
exceeds the FP value, a modem is set in the fallback state.
Service Manual
Field Service Ver. 7.0 Jan. 2009
TCF fallback sequence
48/V.27 ter
24/V27 ter
96/V.17
72/V.17
48/V.27 ter
24/
Y104784-2
Advertisement
Table of Contents
