How do I use ksh TMOUT on 5.2

[Timothy Reed]

hopefully easy question: how  do I access the  TMOUT variable to zap  an
idle user.  Ideally I'd  like to trap it in  a user's login shell.   MKS
doc indicates  that TMOUT's  sends  a SIGALRM,  but  ksh does  not  seem
recognize such a signal on the unix 5.2  system I am running ksh on.   I
manually set TMOUT to '1', and got a 'shell timeout in 60 seconds'  with
every tap of the return key!
Thanks in advance...
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| Timothy Reed - American Chemical Society              |
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