Specifies how to map from FECN field in the Frame
Relay PDU to the EFCI field in ATM cells, in case of
service interworking. This object does not apply to
network interworking.
efciIfFecn(1) and efciIsZero(2) correspond to Mode 1
and Mode 2 (as defined in FRF.8, section 4.3.1.1),
respectively.