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T.38 fax functionality is included in mod_spandsp.

Loopback channel

Loopback/ channels: T.38 pass-through can *NOT* be used with the loopback/ endpoint.

T.38 Passthru

T.38 Passthru: As of v1.6, t38_passthru=true can *NOT* be used if fax_enable_t38 is not also true.

Use Cases

<extension name="tdm_to_sip">
<condition field="destination_number" expression="^1234$">
<action application="t38_gateway" data="peer"/>
<action application="bridge" data="sofia/<profile>/<extension>"/>
<extension name="sip_to_tdm">
<condition field="destination_number" expression="^9876$">
<action application="t38_gateway" data="self"/>
<action application="bridge" data="freetdm/<profile>/<extension>"/>
<extension name="t38_passthru">
<condition field="destination_number" expression="^4321$">
<action application="export" data="fax_enable_t38=true"/> <!-- Required as of v1.6 -->
<action application="export" data="t38_passthru=true"/>
<action application="bridge" data="sofia/<profile>/<extension>"/>

Sofia profile parameters

t38-passthru = true|false|once

See Also