Here's how you can configure a DID to forward to your OBI without configuring a service provider (SP) account:
First create port forwarding on your router. Since I don't have any problems with SIP scanners, I'm still using the defaults, so I port forwarded ports 5060-5062 to forward to my OBI device IP.
Because I have a free DNS account, I have a domain with my name, let's call it:
MyDomain.MyDNS.INFO (this is made up name as I don't want to give you mine!) - however you don't need the domain, you can just use your modem IP, but most routers support auto syncing your modem IP with your domain account (mydns), so it's easier for those folks that occasionally get their modem IP changed by their provider.
The assumption is, you already have a DID account, so for example I have DID's in UK and the free New York one with Call Centric.
When setting up my DID with the UK, I had the option of "register" or "sip". Register is the most common used, where you would then use the user name and password, and server configuration IP's or URL's and configure the OBI to use my UK DID. However; if I instead used SIP option, I would uncheck "register" and enter: "sip:441903300873@MyDomain.MyDNS.INFO:5061" - now when I call the UK number, my OBI rings and I can answer it.
When I set up my Call Centric DID, under preferences, then DID forwarding, normally you would just leave "SIP device (default)" then configure when on your SP accounts on the OBI with your user name, password and callcentric configuration URL or IP settings. If you instead check the bottom box, where you can free type put in:
19142961033@MyDomain.MyDNS.INFO:5061 (that 914 number is made up, it's part of my free NY number sequence) – now when I call this free New York DID from Call Centric, it rings my OBI device too. So all my DID's I forward with this syntax, thereby I don't need a separate SP configured for each DID. My OBI only has SP1=GV and SP2=voip.ms (for E911) – ALL other DID's ring my phone without any other configuration settings.
I think, port 5062 by default really is ringing SP2, note in my case I have the device configured as
voip.ms, but my DID's really are ringing SP2 as I get the different ring pattern as well. I tried to get it to work with other ports, logically I assumed 5061 would be my GV SP, SP1 – but for some reason I could only get this to work on port 5062.
So now I forward on Google, my GV to this free Call Centric DID, and when it rings my house, I'm getting free caller name too. When Call Centric was having network issues, I merely un-forwarded my GV, and my calls came in via SP1(GV) instead – but of course minus the caller name, only the caller number. Even though it's forwarded to Call Centric from GV, if unanswered, GV voice mail picks up and handles the voice mail per normal. However; my UK forwarded DID's just ring and ring unless I could configure the company that provides the free DID's in UK with voice mail – but this company doesn't have it – but that's ok. I supposed if I wanted to get really tricky, I could forward the UK incoming calls to forward to the GV via the advanced call forwarding features of the OBI – the I would have voice mail – but only for the UK DID.
Read further down posts about needing at least one SIP configured SP on OBI:
An earlier article on this suggested I needed a dummy SP just for these DID's – but turns out you don't – it seemed to work with or without the Dummy SP configuration.
