R2511-HP MSR Router Series Voice Command Reference(V5)

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fax protocol
Use fax protocol to configure the type of protocol used for fax communication with other devices.
Use undo fax protocol to restore the default type of protocol used for fax communication with other
devices.
Syntax
fax protocol { t38 | standard-t38 } [ hb-redundancy number | lb-redundancy number ]
fax protocol pcm { g711alaw | g711law }
undo fax protocol
Default
T.38 negotiation mode is used for fax.
Views
Voice entity view
Default command level
2: System level
Parameters
t38: Uses T.38 fax protocol. With this protocol, a fax connection can be set up quickly.
standard-t38: Uses the standard T38 protocol, which supports H.323 and SIP.
lb-redundancy number: The number of low-speed redundant packets. The value range for the number
argument is 0 to 5, and the default is 0.
hb-redundancy number: The number of high-speed redundant packets. The value range for the number
argument is 0 to 2, and the default is 0.
pcm: Enables the transparent transmission in the pass-through mode.
g711alaw: Enables G.711 A-law.
g711ulaw: Enables G.711 -law.
Usage guidelines
With the T.38 protocol adopted, if the call adopts H.323, the fax uses the standard T.38 negotiation
mode stipulated by the H.323; if the call adopts SIP, the fax uses the standard T.38 negotiation mode
stipulated by SIP. If the call control protocol is SIP, this command can be used only for the originator of
the fax request. When a fax request is originated, the fax type is decided according to the configurations.
The receiver of the fax request responds to the originator based on the type of the fax request, and then
establishes a fax call.
Low-speed data refers to the V.21 command data, while high-speed data refers to the TCF and image
data.
To communicate with leading fax terminals in the industry, the standard T.38 protocol must be selected.
Likewise, to communicate with other fax terminals supporting a T.38 protocol, the T.38 protocol must be
adopted. As the leading devices do not support local training mode for fax, the point-to-point training
mode must be adopted in order to implement interworking with the leading devices in the industry.
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