the system and then remove the Compact Flash from the SVMi-4 by simply
pulling it out.
Upgrade Key The SVMi-4 hardware upgrade key is a small passive device that
resembles a calculator battery. It is installed in the upgrade key socket and will
provide 2 additional ports and 16 additional mailbox to the System. This key is
also necessary to operate the SVMi-4 in the 50si.
Installation - Page 32