Secure SIP uses a different URI scheme to non-secure SIP URIs.
A normal, non-secure SIP address has the form:
sip:user@ibm.com:5060
However, to specify the use of secure SIP use sips: in the address instead of sip:, for example:
sips:user@ibm.com:5061
In these examples, the :5060 and :5061 parts of the message are optional. This is because :5060 is the default port for non-secure SIP messages, and :5061 is the default port for secure SIP messages.