Stereo System User Manual
DEFINITY AUDIX System Release 4.0
System Description Pocket Reference 
585-300-214 
Issue 1
May 1999
Design and Operation 
2-2
TN568 Circuit Pack 
TN568 Circuit Pack
The TN568 circuit pack holds the systems main circuitry and performs 
system’s main processing functions, including message routing, 
self-diagnosis, and Alarm Origination. 
Port Board Emulation
The TN568 holds the system’s voice ports. These voice ports 
correspond to the voice ports on a TN754 or TN2181 circuit pack. 
DEFINITY switch releases 7.1 and later recognize the TN568 circuit 
pack. However, the system’s voice ports interact with the switch like the 
voice ports on a TN754 or TN2181 circuit pack regardless of whether the 
system is operating in native or non-native mode. For more information 
about digital port emulation, see Chapter 1.
Flashware
The TN568 circuit pack uses 
flashware
 to store the sequences it uses to 
boot the system and programs specific to the TN568. Flashware are 
programs that reside on flash programmable read-only memory 
(FPROMs). FPROMs are hardware that reside on the TN568 and are 
protected from accidental erases or rewrites. Copies of all the active 
flashware programs are also stored on the hard disk.
If the customer installs software upgrades or fixes, the new program is 
transferred from a MO disk to the hard disk. When the system reboots, 
the new program automatically transfers from the hard disk to the 
FPROMs and replaces the existing flashware.
Hard Disk Drive
The hard disk drive stores the system’s AUDIX software, subscriber 
information and voice messages.
Voice messages that customers may store on the system include voice 
mail, personal greetings, automated attendants, and announcement 
sets—the sets of automated, verbal instructions that compose the 
system’s user interface.
The hard disk drive provides up to 100 hours of voice storage. The 
system comes with a minimum of 10 hours of voice storage. Customers 
can purchase additional voice storage in five-hour blocks. 










