In Emacs, one way to enter these characters is to use `M-x ucs-insert` and then enter the hex code of the separator:

    M-x ucs-insert 1c
    M-x ucs-insert 1d
    M-x ucs-insert 1e
    M-x ucs-insert 1f

for file, group, record, and unit separators. Is there an easier way?