Mis-dial prevention does not require require a patch in release 5.0 and above. Below is part of the documentation for 5.0 on ESA out of the What's New 5.0 NTP:
• Support for the use of Route List Indexes (RLIs) is introduced, whichallows ESA to identify alternate routing for emergency calls, in the event that the standard route is unavailable. This functionality helpsto ensure that an emergency call receives emergency handling byensuring delivery of the call to the appropriate emergency responder,including the ability to locally terminate an ESA call without required use
of loopback trunks.
• On-Site Notification (OSN) output and SNMP traps are enhanced to provide more detailed emergency call information.
• Virtual Office ESA calls can now route directly to the host Call Server for emergency call handling, rather than being redirected.
• Support is introduced for Multiple ESDN. Previously, it was only possibleto configure a single ESDN to be used in placing emergency calls. With CS 1000 Release 5.0 ESA, it is possible to configure up to 16 distinct ESDNs to better suit the needs of a multinational enterprise.
• Implementation of the Misdial Prevention functionality, which provides system administrators with the ability to prevent ESA calls from being made due to an accidentally misdialed ESDN. Cases outlining possible ESDN misdials can be configured for each ESDN entry in use in the enterprise (a notification is made for all calls blocked in this fashion,using the Misdial Prevention functionality).