Rockwell RFX144V24-S23, Руководство дизайнера

Страница: 155 / 198

RFX144V24-S23 and RFX96V24-S23 Modem Designer’s Guide
1070 9-33
9.4 SHORT TRAIN EXAMPLE
An example of the host implementation of V.17 short train in T.30 is shown in Figure 9-29. The diagram shows the proper
setting of control bits EQSV, EQFZ (optional), SHTR, and SETUP. The example starts at the beginning of TCF and the time
line proceeds down the page from that point. It is assumed that the first TCF is successful and EQSV and EQFZ are properly
reset to 0 prior to the long train V.17 reception.
1070F9-29
CALLING STATION
Transmitting TCF (long train V.17).
Configure for FSK receiver.
Transmitting fax message (short train V.17).
CALLED STATION
Receiving TCF (long train V.17).
Host sets EQSV to a 1 prior to the modem
exiting the data mode after determining that
the TCF is good but before the end of the signal.
Setting of EQFZ is optional here.
Host configures for FSK transmitter (leaving
EQSV bit set) and sends CFR.
Host configures for V.17 short train, sets
SHTR bit to a 1, and then sets SETUP bit to
a 1.
Receivting fax message (short train V.17).
Figure 9-29. Example V.17 Short Train Time Line