H3C Technologies H3C MSR 50 - Manual (Page 592)

207
Item Description
Fax Protocol
Configure the protocol used for fax communication with other devices.
• T.38—With this protocol, a fax connection can be set up quickly.
• Standard T.38—It supports H.323 and SIP.
Configure the fax pass-through mode.
• G.711 A-law.
• G.711 μ-law.
The pass-through mode is subject to such factors as loss of packet, jitter, and delay, so the
clocks on both communication sides must be kept synchronized. Only G.711 A-law and
G.711 μ−law are supported, and the VAD function should be disabled.
Number of
Redundant
Low-speed T.38
Packets
Low-speed data refers to the V.21
command data.
This option is configurable when T.38
or standard T.38 is selected as the fax
protocol.
IMPORTANT:
Increasing the number of redundant packets
improves reliability of network transmission and
reduces packet loss ratio. A great amount of
redundant packets, however, can increase
bandwidth consumption to a great extent and
thereby, in the case of low bandwidth, affect the
fax quality seriously. Therefore, the number of
redundant packets should be selected correctly
according to the network bandwidth.
Number of
Redundant
High-speed T.38
Packets
High-speed data refers to the TCF and
image data.
This option is configurable when T.38
or standard T.38 is selected as the fax
protocol.
Max Transmission
Rate of Fax
Specify the maximum fax transmission rate:
24000 bps—Set the maximum transmission rate to 2400 bps.
4800 bps—Negotiate the baud rate first in accordance with the V.27 fax protocol. The
maximum transmission rate is 4800 bps.
9600 bps—Negotiate the baud rate first in accordance with the V.29 fax protocol. The
maximum transmission rate is 9600 bps.
14400 bps—Negotiate the baud rate first in accordance with the V.17 fax protocol. The
maximum transmission rate is 14,400 bps.
Allowed Max Voice Speed of the Codec Protocol—Determines the maximum fax rate
depending on the codec protocol.
• If G.711 is adopted, the maximum fax transmission rate is 14,400 bps and the fax
protocol is V.17.
• If G.723.1 Annex A is adopted, the maximum fax transmission rate is 4800 bps and the
fax protocol is V.27.
• If G.726 is adopted, the maximum fax transmission rate is 14,400 bps and the fax
protocol is V.17.
By default, the Allowed Max Voice Speed of the Codec Protocol option is adopted.
• If G.729 is adopted, the maximum fax transmission rate is 7200 bps and the fax
protocol is V.29.
IMPORTANT:
If an option other than the default option is adopted, the maximum rate is negotiated first in
accordance with the corresponding fax protocol.