H3C Technologies H3C MSR 50 - Manual (Page 593)

208
Item Description
Fax Training
Mode
Specify the fax training mode:
• Local—The gateways participate in the rate training between fax terminals. In this
mode, rate training is performed between fax terminals and gateways, respectively,
and then the receiving gateway sends the training result of the receiving fax terminal to
the transmitting gateway. The transmitting gateway finalizes the packet transmission
rate by comparing the received training result with its own training result.
• Point-to-Point—The gateways do not participate in the rate training between two fax
terminals. In this mode, rate training is performed between two fax terminals and is
transparent to the gateways.
Local Training
Threshold in
Percentage
When rate training is carried on between fax terminals, the transmitting terminal transmits
"zero-filled" TCF data (the filling time per packet is 1.5±10% seconds) to the receiving fax
terminal, and the receiving fax terminal decides whether the current rate is acceptable
according to the received TCF data.
When the percentage of all-ones or all-zeros TCF data to the total number of TCP data is
less than the local training threshold, the current rate training succeeds. Otherwise, the
current rate training fails and you must drop the rate for a local training operation again.
By default, the threshold is 10.
IMPORTANT:
When the local training mode is adopted, use this option to configure the threshold in
percentage. When the point-to-point training mode is adopted, the gateway does not
participate in rate training and the threshold of local training is not applicable.
Signal
Transmission
Mode of Fax
Faculty
In common fax applications, the participating fax terminals negotiate with the standard
faculty (such as V.17 and V.29 rate) by default. It means that they do not send each other
non-standard facilities (NSF) message frames. In some cases such as encrypted fax, both
fax terminals adopt a nonstandard faculty (NSF) to negotiate.
At the start of negotiation, both terminals first exchange NSF message frames, and then
negotiate the subsequent fax faculty for communication. NSF messages are standard T.30
messages and carry private information.
To use a nonstandard faculty for negotiation, the following conditions must be met:
6. Fax terminals must support nonstandard transmission mode.
7. The transmission mode must be set to a nonstandard mode in the POTS and VoIP
entities for both fax terminals.
By default, a standard faculty mode is adopted for fax faculty transmission.
Transmit Energy
Level of a
Gateway Carrier
Usually, the default transmit energy level of the gateway carrier is acceptable. If the fax
cannot be set up yet on the premise that other configurations are correct, you can try to
adjust the transmit energy level of the gateway carrier (that is, transmit energy level
attenuation). A greater level indicates greater energy. A smaller level indicates greater
attenuation.
By default, the transmit energy level of the gateway carrier is –15 dBm.