The following relates to interfacing the FT-897 to linear amplifiers.
See the Files area for the Official Yaesu Errata Sheet in pdf format.
The following is from Chip - K7JA.
"There is some confusing information in the Operating Manual for the
FT-897 regarding interfacing to linear amplifiers. In the initial
manual, both the descriptions and diagram of the ACC jack were
incorrect; in the 2nd printing, which was included in radios with
serial numbers beginning with "03," the diagram was correct, but the
descriptions were still confusing.
The attached PDF file (see Files area for this Yahoo! Group) includes
completely accurate information regarding the interfacing to linear
amplifiers, and we would recommend that you make some copies of these
documents and include them when shipping FT-897s to customers. We
will let you know when the manuals themselves are updated, and
an "insert" sheet will be included at an early date. For the moment,
however, we did not want to delay sending this out to you.
In a nutshell, you use the CAT/Linear jack for T/R switching of an
amplifier, and do not use the ACC jack for any purpose unless you want
to connect ALC.
We sincerely regret this inconvenience, but wish to hasten the
distribution of this information.
Chip Margelli, K7JA
Vertex Standard USA, Inc."