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

    Default: See description           Value: 0-FF

    Hexadecimal code of the sync character to be used on the link.
    The default value depends on the value of the characteristic
    protocol, as follows:

    bisync   32
    chips    32
    ddcmp    96
    genbyte  32
    swift    32

    This attribute is supported only if the characteristic protocol
    is set to bisync, chips, ddcmp, genbyte, or swift. You can modify
    this characteristic only when the entity is disabled.