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

    Default: 10            Value: 1-255

    Maximum number of times that a frame will be retransmitted before
    the local station assumes that a fatal error has occurred. This
    characteristic can be modified only when the entity is disabled.