I'm using the SPA504G (firmware 7.5.4) and having the following issue:
When on active call, softkeys conf and xfer are active. When a second call comes in, the display of the phone changes to "ringing" and softkeys xfer and conf are gone. Is there a setting that disables the display changing the softkeys and let only the leds blinking?
What is the call agent that your SPA phone is connected to ? (UC500 / UC320 / CUCM)
If its a UC box then unfortunately you would not be able to achive it.
On the CCA:
Got to "Configure --> Telephony --> Phone Customization --> Templates"
Here you would have an overview of the templates that are already created and assigned to the phones. You should also be able to view the template assigned to the SPA504 phone.
Once there (not disturbing the existing setup) try creating a new Template using the "Add" button. You will notice the first field is "Alerting" but when you click on the field you just have 3 options to choose from. Which do not have "Endcall, Trnsfr, Hold"
If you compare that to "Connected" state you have multiple options to choose from which include the softkeys you are looking for.
This is by design and cannot be modified as per what we need here.
On the CLI:
alerting Softkey order for alerting (ring out) state
connected Softkey order for connected state
hold Softkey order for HOLD state
idle Softkey order for IDLE state
remote-in-use Softkey order for REMOTE-IN-USE state
Best way to go about this is to contact your local Cisco Rep or the Accounts Team and file a feature request. Will all the new firmwares coming out they might be able to file a business case and have that feature included in the next release.