Library /sys$common/syshlp/nclhelp.hlb set, x25_protocol, dte, x25_address  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Default: No DTE address        Value: DTE-address

    Full address of the DTE. You must give this characteristic a
    value before you enable the DTE.

    Example:

    set x25 protocol dte dte-1 x25 address 123456789