This object specifies SCCP GTT Translation Type (TT)
value when cItpSccpGttGtaTTorSSN is 'tt'.
It specifies SCCP SubSystem Number (SSN) value when
cItpSccpGttGtaTTorSSN is 'ssn'.
A zero value specifies that the TT or the SSN is not
applicable for this GTA entry.