This attribute specifies the maximum desired fax relay rate. This
attribute only applies if modemFaxEncoding is faxRelayOnly or
faxRelayG711G726. The maximum fax relay rate is negotiated and
depends on the setting of maxFaxRelayRate and the fax relay
capabilities on the origination side and destination side. If the
negotiated fax encoding in negotiatedIgEncoding is relay, the
negotiated maximum fax relay rate is available in the fax row of
negotiatedIgRates.