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

    Default: None          Value: True or false

    Specifies whether the use of extended TPDU format should be
    negotiated for the transport connections. Normal format gives
    7-bit sequence numbers and 4-bit credit fields; extended format
    gives 31-bit sequence numbers and 16-bit credit fields. This
    attribute is supported only for class 2 and class 4 protocols.

    set  [node node-id] osi transport template template-id -
         extended format boolean

    Example:

    set osi transport template osit$loop_clns -
         extended format true