Is there any document that explains the Softkeys in more detail?
Beside the abbreviations it is sometimes not clear which function which softkey offers.
In addition to the Quick Start Guides, the SPA 5XX User Guides have explanations of the softkeys:
For SPA 5XX: Keep in mind that with software release 7.3.7 (SIP) and 7.4.2 (SPCP), administrators can create their own softkeys and labels, so depending on the customization of the system, some softkeys may not be described in the general documentation.
If you are looking for the SPA9XX phones, the documentation is here:
Hope this helps.