The example that includes the MIB.ServiceError string shows what happens when the target system is not connected: no association can be established.

ACF.Associate(targetAE (dn "1.3.18.0.2.4.6=NETA;2.9.3.2.
   7.4=(name SSCP1A);1.3.18.0.2.4.12=MYAENAME"))
ACF.AssociateRsp (handle aF)
 
ACF.Associate(targetAE (dn "1.3.18.0.2.4.6=NETB;2.9.3.2.
   7.4=(name SSCP1A);1.3.18.0.2.4.12=OSISMASE"))
MIB.ServiceError(resultCode 817)