With no explanation, label each line with "product-other", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
DTMF
technology
was
referred
to
by
the
trademark
Touch-Tone
.
DTMF:product-other
technology:O
was:O
referred:O
to:O
by:O
the:O
trademark:O
Touch-Tone:product-other
.:O