D-Link DI-1750 Reference Manual page 475

12.7.6 Configure the fax function based on Voice over IP
The way of configuring is to configure fax-protocol t38/rtp in dialpeer of voip. It will employ bypass mode
to processing fax while there is not the two commands.
Our voice products now support two fax mode: T38 and RTP. The fax rate only supports default value
14400pbs. The fax configuration of FXS and FXO is consistent.
1. BYPASS Fax
This is the default mode of D-Link router. It is the recommended mode if you have enough bandwidth.
At present, as our device specifies codec to be g711ar64, g711ur64, g726r32, dg726r40, g727r32 and
g727r40, you can use bypass to fax. PCM coding is a lossless coding mode, therefore the fax signal is
best in this coding mode and certainly this fax occupies the most bandwidth. We sugget you configure
codec to be g711ar64 or g711ur64 when taking this fax mode.
♦ T38 Fax
This fax mode is the most saving mode as to bandwidth. We support faxing with versions more
advanced than cisco12.2.x IOS. When cisco device has been configured with fax protocol t38, we
can communicate with it correctly. What you should care is that the high speed redundancy and low
speed redundancy of our current T38 are both 0 (default value). So when you process t38 fax
communicating with Cisco router, its high speed redundancy and low speed redundancy must also
be 0 (default value). In addition, the two voice codings g729r8 and g729-compatible don't support
t38 fax.
For an example, DLINK1750 and Cisco2620 is processing t38 fax， as demonstrated in the following
figure：
DI-1750 configure：
1750_config#interface e1/0
1750_config_e1/0#ip address 10.1.1.1 255.255.255.0
1750_config_e1/0#exit
1750_config#dial-peer voice 1 pots
1750_config_dialpeer#destination-pattern 4117
1750_config_dialpeer#port 1/0
1750_config_dialpeer#exit
1750_config#dial-peer voice 2 voip
1750_config_dialpeer#session target ipv4:10.1.20.1
1750_config_dialpeer#destination-pattern 4122
1750_config_dialpeer#codec g723r53
1750_config_dialpeer#fax t38
1750_config_dialpeer#exit
1750_config#write
DI-2621 configure：
2621_config#interface e0/0
2621_config_e0/0#ip address 10.1.20.1 255.255.255.0
2621_config_e0/0#exit
2621_config#dial-peer voice 1 pots
2621_config_dialpeer#destination-pattern 4122
2621_config_dialpeer#port 1/0
2621_config_dialpeer#exit
Model Name
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