The Java Virtual Machine (JVM) does not support the special function keys on the VT keyboard. JVM recognizes only restricted set of keys (the common denominator between the various existing keyboards). To provide the user with the functionality of these special function keys there are Virtual Functional Keys (F13..F17) which can be made to appear on the right side of the Java Client toolbar. Clicking on any these keys sends proper code to the host.
To display the Virtual Functional Keys:
Select Options|Use VT Keyboard. The Virtual Functional Keys (F13...F17) appear on the right side of the Java Client toolbar.