Library /sys$common/syshlp/ncphelp.hlb SET, CIRCUIT, DTE dte-addr  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Applies only to X.25 PVCs and DLM circuits. It identifies the
 local  DTE for the circuit. Specify a decimal integer of 1 to 15
 digits.  See the Public Network Information manual for the format
 of the address on your network.  This parameter is optional for
 DLM SVCs and mandatory when you specify an X.25 PVC or DLM PVC
 for the first time.