18.1.7.1. SIP-Q Trunking 
If all requirements for SPE are fulfilled in an OpenScape 4000 system
(see Chapter
3, “Configuration”), the gateway will try to set up a
secure SIP-Q connection to the partner gateway.
If no SIP-Q profile is activated (see "SIP-Connectivity > Section 3.3,
“SIP Trunk Profiles”"), then the payload is encrypted
with MIKEY.
If a SIP-Q profile is activated, then payload encryption can be configured
on the vHG3500.
WBM > Configuration > Voice Gateway > SIP Trunk Profiles
> Select suitable SIP-Q trunk profile > Edit
Figure 376. RTP security mode on the vHG3500 for a SIP-Q trunk
