Both TLS and SRTP are optionally supported on traffic to Simwood (outbound termination) on standard ports.
It should be noted that, whilst this provides encryption between your equipment and ours, your call will not be encrypted on the PSTN or beyond Simwood.
TLS, and thus SRTP, are not currently supported on calls from Simwood to you (e.g. inbound calls to Simwood or hosted numbers). If this is of interest, please let us know.