greetings!
i am not first hand familiar with the ic290, however all my radios
except my ht is an icom. i have been happy with them. perhaps someone with 
personal experience can tell us about that model !
i don't believe that a special mike is needed for pl tones. you can get a pl 
tone generator that is slightly bigger than a postage stamp and it  connects 
internally at the deviation pot. all for less than fifty bucks.
perhaps you mean dtmf (touch tone)?
to access autopatches and other remote control devices you may need a mike 
with a touch tone pad built-in.
73 de kc5gmm
john
--- Maximus/2 3.01
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