This value records whether the PDU containing the failure cause (identified in svcAtmFailedCallPduType) was transmitted by or received on this port, per the description and its transmitted(1)/received(2) enumeration. Combined with svcAtmFailedCallDirection, this tells you precisely who generated the failure decision -- for instance transmitted(1) with caller direction means this switch itself decided to release the call it originated, versus received(1) meaning the far end delivered the bad news. That distinction determines whether you should be examining this switch's own call logic or the peer's response.