ksh 88 (( expression1 ? expression2 : expression 3 )) - HelpPlease

Greetings,

Version 11/16/88

S: HP-UX 11.11, AIX 5.3.0.0, SUN S

Goal is to Page Primary during Mon to Fri between 9 and 5 PM, if not
page on-call.

Time check works fine, one liner doesn't work:

TIME=$(date +%H)

case $TIME in
01|02|03|04|05|06|07|18|19|20|21|22|23|
00)DBA_PAGER="$N_CALL_PAGER" ;;
08|09|10|11|12|13|14|15|16|17)DBA_PAGER=$PRIAMRY_P AGER ;;
esac

DNUM=$(date +%u) # Day Number

(( (DNUM < 6) ? PAGE="N_CALL" : PAGE="PRIMARY" ))

ksh: (DNUM < 6) ? PAGE=N_CALL : PAGE=PRIMARY : syntax error

Not sure what am I doing wrong

For now I am using this:

if (( DNUM 6 ))
then
PAGE="N_CALL";
else
PAGE="PRIMARY"
fi


Regards & Thanks
BN