/mcpvoice service voip no modem passthrough fax protocol none no fax-relay sg3-to-g3 Note: The codec in the regions setting for this interworking must be G.711. As noted previously, an SCCP gateway cannot be set to use T.38 when interworking with CUBE. In order to configure Fax Pass-Through for SIP and H.323 TDM gateways interworking with CUBE, enter: voice service voip no modem passthrough no fax-relay sg3-to-g3 fax protocol pass-through g711ulaw In order to configure T.38 for SIP and H.323 TDM gateways interworking with CUBE, enter: voice service voip no modem passthrough fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback none Note: T.38 Version 3 can be used if it is configured on the CUBE and is supported by the SIP service provider. In order to configure an MGCP TDM gateway for Fax Pass-Through inteworking with CUBE, enter: no mgcp fax-relay sg3-to-g3 no mgcp package fxr-package mgcp fax t38 inhibit no mgcp modem passthrough voip mode nse Note: Since a MGCP gateway does not support upspeeding for Fax Pass-Through, the regions in CUCM between the MGCP gateway and the CUBE must have a codec of G.711. Verify There is currently no verification procedure available for this configuration. Troubleshoot In order to troubleshoot this issue on CUBE, these debugs must be enabled. SIP Enable these debugs for SIP: