Read only. They won't even write to an erased tape like the TK70 will do 
with TK50 media. However, they read fine and they are even more reliable 
than TK70's.
--Chuck

At 06:34 PM 6/11/01 -0500, Brian Chase wrote:
>In checking through the DLT FAQ, I found the following passage:
>
>   Compatibility with the DEC TK50 and TK70 cartridges (CompacTape and
>   CompacTape II, typically in use before 1985) requires the DEC TZ87
>   drive, which is specially certified by DEC.
>
>The FAQ also mentions that the DEC TZ85 and TZ86 drives only accept
>CompacTape-III media.  My question is "To what extent does the TZ87
>support CompacTape and CompacTape-II media?"  Can it read and write
>to those tape formats, or can it only read them?
>
>-brian.