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

    Default: 8             Value: 5-8

    Number of bits in each character. This characteristic is
    supported only when the characteristic protocol is set to
    genbyte. You can modify this characteristic only when the entity
    is disabled.