We have several voice gateways in our network (MGCP) that are set with "mgcp fax t38 inhibit". Without this syntax, I've always had problems with regular fax devices on a Cisco VoIP network. In the normal course of things, this is not an issue. However, recently we've implemented RightFax which requires that T38 be allowed. Now, in order for RightFax endpoints to fax regular fax machines, they have to 10-digit dial through a specific gateway that has its own PRIs and DID ranges. 5 digit RightFax-to-CiscoFax and vice versa does not work. Has anyone else seen or dealt with this issue?