Identifies the target node's line controller for the service circuit
 over which the operation is to take place.  The possibilities are
 as follows.

                BNA  CEC  DA   DL   DLV  DMB
                DMC  DMF  DMP  DMR  DMV  DP
                DQ   DSB  DSF  DSW  DTE  DU
                DUP  DV   DW4  DZ   EIA  EGA
 	       ELA  ERA  ETA  EWA  FPA  FZA
 	       ISA  KDP  KDZ  KL   LLA  MFA
 	       MNA  MXE  PCL  QNA  SVA  TRA
 	       TRE  TRP  UNA  VLA

 Only the synchronous port on the DMF service device may be used.