You do this via the web interface.
1) Login
2) Goto Settings
3) Goto Telephony
4) Goto Connections

Here you simply configure the additional SIP Providers and activate it.

Then follow steps steps 2 and 3 above but this time goto “number assignment” under the Telephony menu. Toggle which phones should get incoming calls from which SIP providers. You can select all phones get all incoming calls or only certain ones. Likewise, you can select the default outgoing SIP Provider for each phone as well.

Hope this helps.

can you tell me, how to set up multiple handsets with multiple sip accounts? I allready tried to setup 2 sip accounts, but don’t know how to bind one sip account to one handset and the second sip to second handset..

Thank you

jan