This is a read-write setting that both selects the default fax transmission rate for this ATM peer and, via its 'none' value, controls whether fax relay is enabled at all. An admin sets this so fax machines connected through the gateway can reliably send and receive faxes over the ATM voice network at an appropriate speed. For example, setting the value to 'none' on a peer that never carries fax traffic disables fax relay entirely, while picking a specific rate turns the feature on for that peer.