antisip.com has a free SIP service.
The registration is done here.
This gives access to a SIP address on the form email@example.com
The settings are as follows:
- Domain: sip.antisip.com
- Protocol: TLS
- Outgoing proxy: sip.antisip.com port 9091
It is possible to use UDP and TCP, but TLS is in most cases the best alternative.
The service works as intended, but the documentation lacks details. There is supposedly an answer machine,
but there is no documentation about which sip address should be used to reach the answer machine.