Cisco Systems H.323 appendix T.38 Fax, HSI INFORMATION Message Support, 3-24

Chapter 3 Provisioning the Cisco HSI

HSI Feature Configuration

Refer to Cisco PGW and Cisco IOS documentation at www.cisco.com for further information on these commands.

T.38 Fax

The T.38 Fax feature enables the HSI to alter a call, initially established for voice, to support a fax transmission.

When a fax call is initiated, a voice call is established. When the terminating gateway detects the fax tone generated by the terminating fax machine, the gateway initiates a T.38 mode request using H.245 procedures from the terminating gateway. If the opposite end of the call acknowledges the T.38 mode request, the initial audio channel is closed and a T.38 fax relay channel is opened.

You enable T.38 Fax for the HSI by specifying static system data parameters. By default, T.38 is provisioned on the HSI by use of the following commands:

prov-add:name=sys_config_static,t38maxval="MaxBit 0x90, FxMaxBuf 0xc8, FxMaxData 0x48" prov-add:name=sys_config_static,t38options="FxFillBit 0, FxTransMMR 0, FxTransJBIG 0, FxRate Trans, FxUdpEC Red"

Table 3-3describes the T.38 static system data parameters. The T.38 parameters for HSI correspond to T.38 parameters proposed in the ITU T.38 recommendation.

Configuring T.38 Fax on the Cisco PSTN Gateway

To enable T.38 Fax throughout the system, you must enable T.38 Fax on the Cisco PGW. On the PGW,

T.38 is enabled through a trunk group property by use of the following MML command:

prov-add:trnkgrpprop:name="2000",FaxSupport="1"

Configuring T.38 Fax on a Cisco IOS H.323 Gateway

Enable T.38 Fax on a Cisco IOS H.323 gateway by issuing the following IOS commands:

voice service voip

fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback none

Configuring T.38 Fax on a Cisco IOS MGCP Gateway

Enable T.38 fax on a Cisco IOS MGCP gateway by issuing the following IOS commands:

voice service voip

fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback none

mgcp package-capability fxr-package

Refer to PGW and Cisco IOS documentation at www.cisco.com for further information on these commands.

HSI INFORMATION Message Support

Cisco CallManager uses the H.225 INFORMATION message during transfer to indicate that ringback tone is on or off. The Cisco HSI now supports this message to correctly interoperate with Cisco CallManager.

	Cisco H.323 Signaling Interface User Guide
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