since 22.214.171.124: Web Interface/V8/Identities#SIP - SIP (Tab)__Call Waiting Indication
Snom300: Navigation Key Down - Phone Behaviour
Snom320: Navigation Key Right or press "Settings" - Phone Behaviour
Snom360: press "Settings" - Phone Behaviour
Snom370: press "Settings" - Phone Behaviour
Snom820: press "Menu" - Call Features/Incoming Calls
Snom870: press "Menu" - Call Features/Incoming Calls
Call Waiting Indication combines two functions:
Starting with 126.96.36.199 Call Waiting setting is per identity.
Starting with 10.1.33.33 by disabling ("off") Call Waiting the phone will send 486 "Busy Here" also for Dial screen is active (user lifted the handset or started Dialing from Idle) and the call attempt is started (Invite send, Ringback received etc.) In older versions, CW "off" was only covering established calls.
for PA1 = on
for PA1+ = off